All Tools | CalculationTime

Southern sky clockThe Crux PerpetualThe Southern Cross clock-calendar: Crux as the hand, the South Celestial Pole as the pivot, and Earth as the movement.Eclipse calculatorEclipse CalculatorEngine-backed global eclipse proximity with the calculation boundary visible.Lunar calendarMoon Phase CalendarDaily lunar illumination, new and full moon events, and hemisphere-aware phase context for planning by the Moon.Dawn sky calculatorSunrise Star MapSunrise time, azimuth and pre-dawn star context on a live calculator route.

Measurement conversionCelsius to Fahrenheit CalculatorWeather, cooking and body-temperature scale conversion Measurement conversionCM to Inches CalculatorProduct, craft and object dimensions from metric to inch Measurement conversionCups to Millilitres CalculatorRecipe cup systems made explicit in millilitres Measurement conversionFahrenheit to Celsius CalculatorRun the offset temperature formula back into Celsius Measurement conversionFeet to Metres CalculatorRoom, trade and height measurements into metric metres Measurement conversionGallons to Litres CalculatorGallon quantities into litres with the gallon system named Measurement conversionInches to Centimetres CalculatorExact 2.54 cm-per-inch conversion for small dimensions Measurement conversionKilograms to Pounds CalculatorMetric mass into pounds for labels, luggage and gym plates Measurement conversionKilograms to Stone CalculatorMetric body weight into stone and pounds context Measurement conversionKM/H to MPH CalculatorMetric speeds into miles per hour Measurement conversionKM to Miles CalculatorRoad, race and map distances in miles Measurement conversionLitres to Gallons CalculatorLitres into US and imperial gallon context Measurement conversionMetres to Feet CalculatorMetric lengths translated back into feet Measurement conversionMiles to Kilometres CalculatorMiles converted into metric route distance Measurement conversionMPH to KM/H CalculatorMiles-per-hour speeds into metric limits and logs Measurement conversionPounds to Kilograms CalculatorPound weights back into SI kilograms

Encoding utilityBase64 Encoder DecoderReversible text and file encoding with the security boundary named Math conversionDecimal to Fraction CalculatorTurn decimal values into inspectable fractions and percentages Physics modelEnergy CalculatorKinetic and potential energy with unit conversion and limits Checksum utilityHash GeneratorLocal SHA and MD5 hashes with fingerprinting limits visible Sky instrumentHorizon Star FinderObserver, horizon and star-position context in one route Trade estimatorMaterial Weight CalculatorConvert dimensions, density and allowance into a weight record Electrical modelOhm's Law CalculatorSolve voltage, current, resistance and power from known values Health estimateOvulation CalculatorCycle-window estimate with assumptions and medical limits visible Physics modelProjectile Motion CalculatorRange, height, flight time and drag-free trajectory proof Health estimateWater Intake CalculatorHydration planning with body, activity and climate assumptions named

Core mathBasic CalculatorEveryday arithmetic with the result trail kept readable Core mathFraction CalculatorFractions, mixed numbers and decimal equivalents Core mathPercent CalculatorPercent of, percent change and reverse percent with the base visible Core mathScientific CalculatorPowers, roots, logs, trig and function-mode checks

Work and payrollBillable Hours CalculatorConvert utilization, rate and available hours into revenue Work and payrollHourly Rate CalculatorPrice a working hour with the time base visible Work and payrollHourly to Salary CalculatorAnnualize an hourly rate from weekly hours and paid weeks Work and payrollOvertime CalculatorSeparate ordinary hours from premium overtime pay Work and payrollPayroll CalculatorGross pay from hours, rate, overtime and period assumptions Work and payrollProrated Salary CalculatorEstimate partial-period salary from worked days Work and payrollSalary to Hourly CalculatorUnbundle annual salary into an hourly equivalent Work and payrollTime Card CalculatorTrace clocked time into a payroll-ready work record

Time & DateAge CalculatorCalculate age from a birth date to a chosen date, with years, months and days shown clearly.MoneyAmortization CalculatorBuild a fixed-rate loan amortization check with monthly payment, balance after a chosen payment, interest paid and extra-payment impact.Finance BasicsAPY CalculatorCalculate annual percentage yield from a stated interest rate and compounding frequency, with ending balance, earned interest and a printable savings comparison record.Math & MeasurementArea CalculatorCalculate rectangular area from length and width, with measured area, planning allowance, unit-basis notes and a printable quote, classroom or job record.Home, Trade & ConstructionAsphalt CalculatorEstimate asphalt tonnage from paving length, width and compacted depth, with cubic yards, short tons, metric tonnes, waste allowance, cost estimate and a printable paving quote note.MoneyAuto Loan CalculatorEstimate a car loan payment from vehicle price, down payment, trade-in, sales tax, fees, interest rate and loan term.Percentage & MathAverage CalculatorCalculate the mean, median, mode and range of any list of numbers in a live sandbox - add or remove values freely and every statistic updates instantly, with a printable custom report and a standalone statistics reference sheet.Work & PayrollBillable Hours CalculatorEstimate weekly, monthly and annual billable capacity after non-billable work, leave weeks and utilisation limits, with a printable capacity and revenue record.Developer & Number BasesBinary / Hex Converter CalculatorConvert a whole decimal number into binary, hexadecimal and octal notation with bit-length and byte-count checks.Work, Payroll & TimeBiweekly Pay CalculatorCalculate gross biweekly pay from hourly rate, regular hours, overtime hours and optional pretax deductions, with clear pay-period assumptions and a printable payroll worksheet.HealthBMI Calculator - Adult Body Mass Index, Healthy Weight Range & BMI PrimeCalculate adult BMI from metric or US units, see the BMI category, healthy weight range, BMI Prime, Ponderal Index and clear health limitations.Trade & ConstructionBoard Foot CalculatorCalculate board feet for lumber from thickness, width, length, quantity and waste allowance, with cubic-foot cross-checks, optional material cost and a printable lumber order worksheet.BusinessBreak-Even CalculatorFind the sales volume and revenue needed to cover fixed costs, variable costs and optional target profit.ConstructionBrick CalculatorEstimate brick count for a rectangular wall from wall size, brick face size, mortar joint allowance, openings and waste.Finance & Household BudgetingBudget CalculatorBuild a monthly budget from income, housing, bills, debt, savings and everyday spending, with surplus/shortfall, savings-rate and printable household budget worksheet outputs.FinanceBudget Split CalculatorSplit monthly income into needs, wants, savings and debt payments, then print a simple budget record.Work & PayrollBusiness Days CalculatorCount weekday business days between two dates, with optional start-date and end-date inclusion controls.Finance & BusinessCAGR CalculatorCalculate compound annual growth rate from a starting value, ending value and time period, with growth-multiple, annualised return, scenario comparison and a printable investment or business-growth record.Home, Trade & ConstructionCarpet CalculatorEstimate carpet area, waste allowance, roll length and optional material cost from room measurements and carpet roll width.Finance BasicsCD CalculatorCalculate certificate of deposit growth from opening deposit, APY and term length, with ending balance, interest earned, early-withdrawal note and a printable bank-offer comparison record.ConversionsCentimetres to Feet and Inches CalculatorConvert centimetres to feet and inches for height records, product dimensions, cut notes and classroom worksheets.Parenting & AustraliaChildcare Subsidy (CCS) CalculatorEstimate Australian Child Care Subsidy from family income, service type, session fee, session hours and eligible subsidised hours.Core MathematicsCircle CalculatorCalculate circle area, circumference, diameter/radius checks, and optional planning allowance from a radius or diameter.Math & MeasurementCircumference CalculatorCalculate the distance around a circle from radius or diameter, with area, allowance and a printable measurement record.Work & PayrollCommission CalculatorCalculate sales commission from sale amount, commission rate, base pay and returns or chargebacks.Money EducationCompound Growth CalculatorProject repeated percentage growth from a starting value and turn the full compounding path into a visible period-by-period story.MoneyCompound Interest CalculatorProject compound growth from a starting balance, regular contributions, interest rate, compounding frequency and time horizon.Health & BodyConception Date CalculatorEstimate conception date and fertile-window timing from due date, last menstrual period or ultrasound gestational age, with clear medical limitations.Construction & TradeConcrete Bags CalculatorEstimate ready-mix concrete bags from slab length, width, depth, bag yield and waste allowance, with cubic metres, litres and bag count kept visible for quote notes and job records.Home, Trade & ConstructionConcrete Block CalculatorEstimate concrete blocks for a wall from wall length and height, with block size, openings, waste allowance, mortar-joint basis, cost estimate and a printable block takeoff record.Home, Trade & ConstructionConcrete CalculatorEstimate concrete volume for a rectangular pour from length, width and thickness, with cubic yards, cubic metres, bag estimates, ready-mix cost, visible overage and a printable pour-planning record.Home, Trade & ConstructionConcrete Footing CalculatorEstimate concrete for strip footings, wall footings and post footings from length, width and depth, with cubic yards, cubic metres, bag checks, waste allowance and a printable footing pour note.Home, Trade & ConstructionConcrete Slab CalculatorCalculate concrete slab volume from length, width and thickness, with cubic yards, cubic metres, bag estimates, waste allowance, optional cost and a printable pour record.TradesConcrete Volume CalculatorEstimate concrete volume for slabs, footings and rectangular pours from length, width, depth and waste allowance.Trade & ConstructionContractor Markup & Margin CalculatorConvert cost, markup and margin into a contractor selling price and gross profit.Measurement & Unit ConversionCooking & Volume ConverterConvert cups, fluid ounces, millilitres, litres, quarts, gallons, pints, tablespoons and teaspoons in one bidirectional liquid-volume tool with US cooking-volume factors and printable proof.Date & TimeCountdown TimerCalculate days, hours, minutes and seconds remaining until a target date-time, or elapsed after the event passes, with unit-by-unit proof.Trade & ConstructionCountertop Square Footage CalculatorCalculate countertop square footage from length and depth, add backsplash area, subtract cutouts, apply waste allowance and print a quote-ready measurement record.Date & TimeCounts Per Minute CalculatorCalculate counts per minute from a count and elapsed time, with counts per second, counts per hour and five-minute projection checks.Measurement & Unit ConversionCups to Grams CalculatorConvert cups to grams using an entered grams-per-cup density for flour, sugar, butter, oats, powders and recipe worksheets, with tablespoon, millilitre, serving and printable kitchen record outputs.Measurement & GeometryCylinder Volume CalculatorCalculate cylinder volume from radius or diameter and height, with litres, cubic metres, cubic feet and optional allowance shown for tanks, tubes, posts and classroom work.Time & DateDate CalculatorAdd or subtract calendar days from a start date using clear Gregorian calendar arithmetic.Time & DateDays Between Dates CalculatorCalculate elapsed days between two calendar dates, with inclusive-date options, weeks-and-days breakdown and a printable date-span record.FinanceDebt Payoff CalculatorEstimate how long it will take to pay off a debt from balance, APR and monthly payment, with optional extra payment and fee fields kept visible.Finance & MoneyDebt Snowball vs Avalanche CalculatorCompare debt snowball (smallest balance first) against debt avalanche (highest rate first), with months to debt-free and total interest for each.Finance & Household BudgetingDebt-to-Income Ratio CalculatorCalculate front-end and back-end debt-to-income ratios from monthly income, housing cost and recurring debt payments for mortgage, rental, refinance and budget-prep records.Trade & ConstructionDeck Board CalculatorEstimate deck board count, running metres, waste allowance and optional material cost from deck size, board width, spacing and board length.Science & Everyday MathDensity CalculatorCalculate density from mass and volume, with g/mL, g/cm³, kg/m³ and lb/ft³ cross-checks, uncertainty range, unit-basis notes and a printable lab, material or classroom density record.Freight & LogisticsDimensional Weight CalculatorCalculate freight chargeable weight from parcel dimensions, actual weight and carrier divisor.Math & PercentagesDiscount CalculatorCalculate sale price, discount amount and optional tax from an original price and discount percentage, with a printable sale-tag, coupon or quote check.Time, Distance & FitnessDistance CalculatorCalculate distance from average speed and elapsed time, with mile, kilometre, metre, pace and printable trip or classroom record outputs.Work & PayrollDouble Time CalculatorCalculate double-time pay from regular hours, double-time hours, base hourly rate and optional extra gross pay, with a printable payroll record.Money EducationDrawdown Recovery CalculatorCalculate the percentage gain and number of growth periods needed to recover from a drawdown.Trade & ConstructionDrywall CalculatorEstimate plasterboard or drywall sheets from wall length, height, openings, sheet size and waste allowance.HR & Business · AustraliaEmployee True Cost (Oncost) Calculator — AustraliaCalculate the total annual cost of employing someone in Australia including superannuation, leave loading, workers compensation and payroll tax. Shows total oncost percentage above salary.Trade Compliance & CarbonEU CBAM Calculator - Carbon Border Adjustment Cost & Embedded EmissionsEstimate EU CBAM certificate cost for imports of steel, cement, aluminium, fertilisers, hydrogen and electricity. Calculate embedded emissions, carbon price exposure and per-unit CBAM cost.AutomotiveEV vs Petrol Running Cost CalculatorCompare annual petrol and electric vehicle energy costs and estimate payback on an EV price premium.Events & HospitalityEvent Catering Quantity CalculatorEstimate food and drink quantities for an event from guest count, meal format and event duration.Date & TimeEvent Time AnnouncerTurn an event time in one UTC offset into clear audience-local announcements, with UTC proof, backup offset and date-shift wording.Home, Trade & ConstructionExcavation CalculatorEstimate excavation volume from length, width and depth, with cubic yards, cubic metres, loose spoil, truckload checks, cost estimate and a printable dig or quote note.ConversionsFeet and Inches to Centimetres CalculatorConvert feet and inches directly into centimetres, metres and total inches with the exact international-inch basis and a printable height or measurement record.Measurement & Unit ConversionFeet and Inches to Decimal Feet CalculatorConvert feet and inches to decimal feet for cut lists, room measurements, estimating sheets and classroom work, with metric cross-checks and a printable measurement record.ConversionsFeet and Inches to Metres and Centimetres CalculatorConvert height, product dimensions or building measurements from feet and inches into metres and centimetres using the exact international inch definition and a printable measurement record.Construction & TradeFence CalculatorEstimate fence panels, posts, total run length and material-only cost from a straight or rectangular fence layout.Study & SchoolFinal Grade CalculatorFind the score needed on a final exam or project to reach a target course grade under clear weighted-grade assumptions.TradesFlooring Area CalculatorAdd rectangular room sections, include a clear waste allowance and print a flooring measurement record for quotes, classrooms and job notes.Percentage & MathFraction CalculatorAdd, subtract, multiply or divide two fractions, reduce the answer to simplest form, show the mixed number and decimal check, and print a classroom or measurement worksheet record.Legal & US FederalFRCP Rule 6 Deadline CalculatorCount a current FRCP Rule 6(a)(1) days-based federal civil deadline from a triggering date, including intermediate weekends and federal legal holidays, then roll only the last day when required.BusinessFreelance Rate CalculatorWork backwards from target income, expenses, taxes, unpaid time and billable hours to estimate a sustainable freelance hourly rate.Finance & EverydayFuel Cost CalculatorEstimate trip fuel cost from distance, fuel economy, fuel price and optional tolls or parking, with litres and gallons shown clearly.Percentage, Math & Everyday ArithmeticGCF CalculatorFind the greatest common factor of two or three whole numbers, with Euclidean-algorithm steps, factor-list checks, LCM relationship, classroom wording and a printable arithmetic worksheet record.Math & StatisticsGPA CalculatorCalculate a weighted grade point average from course grade points and credit hours, with the credit-weighted method shown clearly.Study & SchoolGrade Percentage CalculatorTurn points earned and points possible into a percentage score, with an example letter band and clear extra-credit notes.Measurement & Unit ConversionGrams to Cups CalculatorConvert grams to cups using an entered grams-per-cup density for flour, sugar, butter, oats, powders and classroom worksheets, with tablespoon/teaspoon cross-checks, recipe scaling and a printable kitchen measurement record.Trade & ConstructionGravel CalculatorEstimate gravel volume and approximate weight from area, depth, waste allowance and bulk density, with a printable landscaping or driveway quote note.BusinessGross Margin CalculatorCalculate gross margin from revenue and cost of goods sold, with gross profit, cost ratio, markup cross-check, scenario rows and a printable margin record.Work & PayrollGross Pay CalculatorCalculate hourly gross pay from regular hours, overtime hours, hourly rate, overtime multiplier and any one-time bonus before deductions, with regular pay, overtime pay, effective rate and a printable payroll arithmetic record.Home & EnergyHeat Pump ROI CalculatorEstimate heat pump payback by comparing current annual heating cost with heat pump running cost and installed cost.Education · AustraliaHECS HELP Repayment CalculatorEstimate your compulsory HECS-HELP repayment using current ATO marginal study and training loan repayment thresholds.Measurement & Unit ConversionHeight Converter CalculatorConvert height between centimetres, metres, inches and feet-and-inches for medical forms, sports profiles, school worksheets and measurement records, with rounding notes and a printable height report.Work & PayrollHourly Paycheck CalculatorEstimate an hourly paycheck from regular hours, overtime hours, hourly rate, pre-tax deductions and estimated withholding, with first-screen gross pay, taxable pay, withholding, deductions and take-home lines.Work & PayrollHourly Rate CalculatorConvert annual salary or project fees into transparent hourly rates using entered work hours.Work & PayrollHourly to Salary CalculatorConvert hourly pay into weekly, monthly and annual gross salary equivalents using visible hours and paid-week assumptions.Time, Work & PayrollHours Between Times CalculatorCalculate hours between two clock times, including overnight spans, unpaid breaks, decimal-hour output, rounded hours, gross-value notes and a printable shift, appointment, classroom or job-time record.Time & DateHours to Decimal CalculatorConvert decimal hours to hours and minutes, or hours and minutes to decimal hours, with timesheet examples and printable proof.Immigration & LegalImmigration 90-Day Date CounterFind the first date more than 90 days after US admission, with the day-90 and exactly-90-days-after markers shown for caution.ConversionsImperial Gallons to Litres CalculatorConvert UK imperial gallons to litres, with optional allowance kept separate for tanks, fuel logs, brewing, garden and classroom records.Finance & Household BudgetingInflation CalculatorEstimate how inflation changes purchasing power, future cost and real value over time from an amount, annual inflation rate and number of years, with a printable budget or classroom record.Home, Trade & ConstructionInsulation CalculatorEstimate insulation area, batt or roll count and material cost from wall, ceiling or floor measurements, with opening deductions, waste allowance, coverage per pack and a printable homeowner, tradie or classroom job note.Date & TimeInternational Meeting PlannerPlan a meeting across manual UTC offsets, including host time, participant local time, target end time and a backup participant clock.Finance & Capital MarketsIPO Lock-up Expiry CalculatorCalculate the expiry date of an IPO lock-up period and show common 90, 180 and 270 day windows.Finance & MoneyIRR CalculatorEstimate internal rate of return from an initial outflow, annual cash flows and terminal value using a transparent NPV zero-crossing method.Measurement & Unit ConversionLand Area ConverterConvert acres, hectares, square feet and square metres in one bidirectional land-area tool with exact international-foot and metric factors plus printable proof.Health & FitnessLean Body Mass CalculatorLean Body Mass Calculator estimates lean mass, fat mass and lean BMI from body weight, body-fat percentage and height.Finance & MoneyLease Amortization CalculatorEstimate a lease liability, right-of-use asset basis and first-period amortization from fixed payments, discount rate, term, payments already made and initial direct costs.Percentage, Math & Everyday ArithmeticLeast Common Multiple CalculatorFind the least common multiple of two or three whole numbers, with prime-factor notes, common-multiple checks, classroom wording and a printable arithmetic worksheet record.Measurement & Unit ConversionLength ConverterConvert millimetres, centimetres, metres, inches, feet, yards, kilometres and miles in one bidirectional length tool with the exact unit basis visible.ConstructionLinear Feet CalculatorCalculate total linear feet from repeated lengths, optional extra runs, waste allowance and unit price for trim, boards, fencing, cable or edging.ConversionsLitres to Imperial Gallons CalculatorConvert litres to UK imperial gallons, with optional allowance kept separate for fuel, garden, tank, brewing, classroom and trade records.Measurement & ConversionLitres to Pints CalculatorConvert litres to US liquid pints and imperial pints with the formula, system difference and printable volume record kept visible.Finance & MoneyLoan CalculatorCalculate an estimated fixed loan payment from amount, APR, term and optional upfront/down-payment adjustments, with total interest, payoff total, scenario comparison and a printable loan quote record.MoneyLoan Payment CalculatorEstimate the monthly payment, total repayment and interest cost for a fixed-rate amortising loan.Finance & BusinessMargin CalculatorCalculate gross margin, gross profit, markup percentage and target-price checks from selling price, cost, quantity and optional discount, with a printable pricing record.BusinessMargin Markup CalculatorConvert cost, markup and profit margin into selling price, gross profit and the difference between markup and margin.Finance & BusinessMarkup CalculatorCalculate selling price, markup amount, markup percentage and gross margin from cost, target markup and optional quantity, with a printable pricing note.BusinessMeeting Cost CalculatorEstimate the labour cost of a meeting from attendee count, average hourly cost, meeting length and preparation time.Measurement & ConversionMeters to Feet and Inches CalculatorConvert meters into feet and inches, decimal feet, total inches and centimeters with the exact meter-to-inch basis and printable height or measurement record visible.ConversionsMetres and Centimetres to Feet and Inches CalculatorConvert metric lengths from metres and centimetres into feet and inches using the exact international inch definition.Time & WorkMilitary Time CalculatorConvert regular 12-hour clock time to military time and 24-hour time, with minutes, decimal-hour cross-checks, shift-note context and a printable time-conversion record.Time & DateMinutes to Decimal Hours CalculatorConvert minutes into decimal hours for timesheets, billing, payroll prep and classroom checks, with rounding kept separate from the raw answer.FinanceMortgage CalculatorEstimate a US-style monthly mortgage payment with principal and interest, property tax, home insurance, PMI and HOA shown separately for a clearer house-buying budget.Finance & MoneyMortgage Repayment CalculatorEstimate fixed-rate mortgage repayments from home price, down payment, rate, term, and optional monthly tax or insurance costs.Travel, Fuel & Unit ConversionMPG CalculatorCalculate miles per gallon, gallons used, fuel cost and emissions-style fuel notes from distance, fuel volume and price for road trips, fleet logs, reimbursement records and classroom worksheets, with a printable mileage report.Trade & ConstructionMulch CalculatorEstimate mulch volume from bed length, width, depth, allowance and bag size, with cubic metres, litres and bag counts shown together.MathNumber Format ConverterConvert decimals, fractions and percentages in one bidirectional number-format tool with simplified fractions, percent output and printable proof.Health & Care PlanningNurse Staffing Planning CalculatorEstimate nurses required per shift and per day from patient count, a user-entered planning ratio and daily shift count; not a legal staffing mandate.Health & FitnessOne Rep Max CalculatorOne Rep Max Calculator estimates 1RM from lifted weight and reps using Epley and Brzycki checks.Date & TimeOnline StopwatchRecord elapsed stopwatch time, lap count, fastest lap and latest split as a printable timing record.Work & PayrollOvertime CalculatorSplit one shift into regular time and overtime, deduct unpaid breaks, and estimate gross pay from a base rate and overtime multiplier.Health & LifecycleOvulation / Fertility CalculatorEstimate ovulation date, fertile window and next period from last menstrual period, cycle length and luteal phase.Time, Distance & FitnessPace CalculatorCalculate pace per mile and per kilometre from distance and finish time for running, walking, cycling, race planning and printable training records.Trade & ConstructionPaint CalculatorEstimate wall paint litres, cans and material cost from room length, width, height, openings, coats, coverage rate and waste allowance, with a printable job note.Trade & ConstructionPaint Coverage CalculatorEstimate paint quantity from wall length, wall height, openings, coats, coverage rate and waste allowance, with a printable room-painting record.Freight & LogisticsPallet Space OptimiserEstimate pallet count from truck or container dimensions, pallet size and cargo height.Developer & ITPassword GeneratorGenerate a deterministic password-strength estimate from length and character sets, with entropy bits, search-space size and safety notes for using a real password manager.Construction & TradePaver CalculatorEstimate paving stones from area, paver size, waste allowance and optional per-paver price, with the formula and ordering assumptions shown clearly.Work & PayrollPay Raise CalculatorCalculate a pay raise from current salary or hourly pay, with new pay, annual difference, percentage increase, bonus comparison, inflation lens and multi-year pay trajectory.Finance & MoneyPayment / Interest Equivalent CalculatorCompare the same loan across payment, rate and term scenarios to see what monthly payment, total interest and equivalent APR imply.Money EducationPenny Doubling CalculatorTurn the classic penny-doubling puzzle into a visible exponential-growth story with milestones, final jump and complete period timeline.MathPercent CalculatorCalculate what percent a part is of a whole, with visible arithmetic, denominator safeguards and a printable percentage record for worksheets, reports and quote checks.Math & StatisticsPercent Error CalculatorCalculate percent error between an experimental or measured value and an accepted reference value, with absolute and signed error shown clearly.Math & PercentagesPercent Off CalculatorCalculate the sale price, amount saved and optional tax total when a percentage is taken off an original price.Math & StatisticsPercent Yield CalculatorCalculate chemistry percent yield from actual yield and theoretical yield, with mass basis, loss amount, signed difference, formula, caveats and a printable lab worksheet record.MathPercentage Change CalculatorFind the percentage increase or decrease between an original value and a new value, with baseline sensitivity, visual proof and a printable comparison record.MathPercentage of a Number CalculatorCalculate a percentage of any number, with the amount, remaining value and printable working shown clearly.Math & MeasurementPerimeter CalculatorCalculate the perimeter of a rectangle from length and width, with optional allowance for edging, trim, fencing, borders or classroom worksheets.Finance & MoneyPersonal Loan CalculatorEstimate a personal loan payment from financed balance, APR, term, fees, deposit, and optional extra monthly payment.Home & ConstructionPool Volume CalculatorEstimate swimming pool volume from length, width, average depth and shape, with litres and US gallons shown for treatment, heating and maintenance notes.Health & LifecyclePregnancy Due Date CalculatorEstimate due date, gestational age and trimester from last menstrual period, conception, IVF transfer or ultrasound dating.MoneyPresent Value CalculatorDiscount a future amount back to today using an annual rate, time horizon and compounding frequency.Percentage & MathProbability CalculatorCalculate probability from favourable outcomes and total outcomes, then show odds, complement probability, repeated-trial chance and a printable classroom or risk-note record.BusinessProfit Margin CalculatorCalculate gross profit, profit margin percentage and markup from cost and selling price, with discounts and extra costs kept visible.Work & PayrollProrated Salary CalculatorCalculate prorated gross salary for a partial year, pay period or contract using annual salary, paid days and optional unpaid leave.Math & GeometryPythagorean Theorem CalculatorFind the hypotenuse of a right triangle from two legs, with square-sum proof, optional check length and a printable classroom or layout record.TradesQuote Profit CalculatorCheck quoted job revenue against materials, labour, overhead, contingency and tax before sending a price.Math & StatisticsRandom Number Generator CalculatorGenerate a reproducible pseudo-random number between two limits, with optional integer mode, seed, draw count and range-size proof.MathRange CalculatorFind the range of up to six numbers, with the minimum, maximum and difference shown for classroom, score and measurement checks.MathRatio CalculatorSimplify two-number ratios, scale them to a new total, and show part-to-part and part-to-whole percentages with a printable worksheet record.Construction & TradeRebar CalculatorEstimate rebar pieces, total bar length and material cost for a rectangular slab or pad using spacing, edge cover, lap allowance and a printable job note.Home, Trade & ConstructionRectangle Area CalculatorCalculate rectangle area from length and width, with square feet, square metres, optional waste allowance, cost estimate and a printable measurement record.FinanceRefinance CalculatorCompare an existing loan with a refinance offer using payment, monthly saving, closing costs and break-even month.Finance & MoneyRent CalculatorRent Calculator estimates total monthly rent burden from rent, utilities, renters insurance and income.Real Estate & AustraliaRental Yield CalculatorCalculate gross and net rental yield from property value, weekly rent and annual holding costs.FinanceROI CalculatorCalculate return on investment from amount invested, final value, extra costs and optional time held, with a printable investment comparison record.Trade & ConstructionRoofing CalculatorCalculate roof area, pitch-adjusted slope factor, waste allowance and rounded roofing packs for a printable homeowner, supplier or tradie quote note.Percentage & MathRounding CalculatorRound a number to decimal places or a chosen increment, with nearest, up and down modes, formula notes and a printable rounding-rule record.Time, Work & PayrollSalary CalculatorConvert annual salary into monthly, biweekly, weekly, daily and hourly gross equivalents, with paid-week and weekly-hour assumptions, unpaid-hours comparison and a printable job-offer or pay-review worksheet.Work & PayrollSalary to Hourly CalculatorConvert annual salary into an hourly rate, weekly pay and monthly pay using visible work-hour assumptions.Finance & Everyday MoneySales Tax CalculatorCalculate sales tax, discount, shipping and final checkout total from a subtotal and tax rate, with the tax amount kept separate for receipts, quotes and classroom examples.ConstructionSand CalculatorEstimate sand volume, cubic yards, tons and optional material cost from area, depth, waste allowance and bulk density.Finance & MoneySavings CalculatorEstimate the monthly saving needed to reach a goal from current savings, time to goal and optional interest rate.MathScientific Notation CalculatorConvert a number into scientific notation, standard decimal form and order-of-magnitude wording with the formula and rounding basis visible.FinanceSimple Interest CalculatorCalculate simple interest, total repayment and effective yearly interest from principal, rate and time.Math & StatisticsSlope CalculatorCalculate the slope between two coordinate points, show the rise-over-run formula, flag vertical lines and print a clean classroom or drawing worksheet.Home, Trade & ConstructionSod CalculatorEstimate sod or turf rolls from lawn length, width and coverage, with square feet, square yards, square metres, waste allowance, roll count, pallet check, cost estimate and a printable lawn job note.Home & EnergySolar Panel Payback CalculatorEstimate solar payback from system size, upfront cost, electricity tariff, feed-in tariff and household usage.Time, Distance & FitnessSpeed CalculatorCalculate speed from distance and time, with miles per hour, kilometres per hour, metres per second and pace kept visible for travel, sport, classroom and job records.Measurement & Unit ConversionSpeed Unit ConverterConvert miles per hour, kilometres per hour, metres per second and knots in one bidirectional speed-unit tool with exact distance-time proof and printable output.Measurement & ConversionSquare Feet to Square Yards CalculatorConvert square feet to square yards, square metres and optional ordering area with the 1 square yard = 9 square feet formula shown clearly.TradesSquare Footage CalculatorCalculate square feet, square yards and square metres from length and width, with a practical waste allowance for flooring, decking, sheet goods and room measurements.Unit & Measurement ConversionSquare Inches to Square Feet CalculatorConvert square inches into square feet, square metres and optional planning area for drawings, tile pieces, product dimensions and classroom worksheets.Percentage & MathSquare Root CalculatorFind the principal square root of a number, its square check and an optional rounded classroom or worksheet result.Measurement & ConversionSquare Yards to Square Feet CalculatorConvert square yards to square feet, square metres and optional ordering area with the 1 square yard = 9 square feet formula shown clearly.Trade & ConstructionStair CalculatorEstimate stair risers, tread going, total run and a 2R+G comfort check from floor height and preferred riser height.Real Estate & AustraliaStamp Duty Calculator - NSW, VIC & QLDEstimate residential transfer duty for NSW, Victoria and Queensland from a property value and buyer type using visible sliding-scale rules.Math & StatisticsStandard Deviation CalculatorCalculate mean, population standard deviation and sample standard deviation for a small data set, with the squared-difference method visible.Business & AccountingStraight-Line Depreciation CalculatorCalculate straight-line depreciation, annual expense, accumulated depreciation and book value after a selected year.Developer & ITSubnet CalculatorCalculate IPv4 network address, broadcast address, usable host range, wildcard mask and host count from an IP address and CIDR prefix.Math & MeasurementSurface Area CalculatorCalculate rectangular-prism surface area from length, width and height, with optional planning allowance for wrapping, coating, packaging and classroom geometry records.Measurement & Unit ConversionTemperature ConverterConvert Celsius, Fahrenheit and Kelvin in one bidirectional temperature tool with offset formulas, absolute-zero guardrails and printable proof.Trade & ConstructionTile CalculatorEstimate floor or wall tiles from area, tile size, grout gap, waste allowance and box size.Date & TimeTime Add or Subtract CalculatorTime Add or Subtract Calculator adds or subtracts hours, minutes and seconds, then shows the wrapped clock-day result.Work & PayrollTime and a Half CalculatorCalculate time-and-a-half pay from regular hours, time-and-a-half hours, base hourly rate and optional extra pay, with the formula and printable payroll note kept visible.Time & DateTime CalculatorAdd or subtract time durations and see the result normalised into days, hours, minutes and seconds.Time, Work & PayrollTime Card CalculatorTotal a weekly time card from daily hours, unpaid breaks, overtime threshold and hourly rate, with regular/overtime split, gross-pay estimate and a printable work record for payroll prep, invoices and classroom examples.Date & TimeTime Difference CalculatorFind the clock difference between two times, with optional overnight handling and decimal-hour proof.Time & DateTime Duration CalculatorCalculate the hours and minutes between two times, including overnight spans.Date/Time/CalendarTime Unit ConverterConvert seconds, minutes, hours, days and weeks in one bidirectional fixed-duration tool with SI-second proof and printable output.Time & DateTime Until CalculatorCalculate the exact time until a target date and time from an editable current date and time.Time & DateTime Zone CalculatorConvert a clock time between two UTC offsets, check date rollover and prepare a printable meeting-time record with the assumptions kept visible.Date & TimeTime Zone ConverterConvert a source clock time from one manual UTC offset to another, including date-shift notes and an extra offset check.Percentage & MoneyTip CalculatorCalculate a restaurant tip, final bill total and per-person split from the bill amount, tip percentage, tax and party size.Home, Trade & ConstructionTopsoil CalculatorEstimate topsoil volume from length, width and depth, with cubic-yard, cubic-foot, cubic-metre, litre, bag and bulk-order checks plus a printable garden or landscaping job note.Math & MeasurementTriangle Area CalculatorCalculate triangle area from base and height, with side-length cross-checks, optional planning allowance and a printable geometry record.ConversionsUnit ConverterConvert common length, weight, volume and temperature units with the formula, exact basis and printable conversion record kept visible.Everyday MathUnit Price CalculatorCompare two package prices by price per unit, with the cheaper option, unit-price gap and printable shopping, classroom or supplier quote note shown clearly.Math & StatisticsVariance CalculatorCalculate population variance and sample variance for a small data set, with the mean, squared differences and denominator shown clearly.BusinessVAT / GST CalculatorAdd tax to a net price, remove tax from a gross price, and show the tax amount clearly for receipts, quotes and classroom checks.Measurement & ConstructionVolume CalculatorCalculate the volume of a rectangular box, room, container or prism from length, width and height, with litres, cubic metres and cubic feet shown for checking.Measurement & Unit ConversionVolume ConverterConvert cubic feet, cubic metres and cubic yards in one bidirectional cubic-volume tool with exact international-foot factors and printable proof.Construction & HomeWallpaper CalculatorEstimate wallpaper rolls from wall width, wall height, roll size, repeat allowance and openings, with the formula and printable room note kept visible.Events & WeddingsWedding Budget CalculatorBuild a wedding budget from guests, catering, venue, photography, music, flowers, other costs and contingency.Photography / EventsWedding Photography Rate CalculatorEstimate a minimum wedding photography package rate from target salary, business costs, booking count, hours and profit margin.Time & DateWeek Number CalculatorFind the ISO week number, ISO week-year and weekday for a calendar date, with a simple year-boundary explanation.Measurement & Unit ConversionWeight & Mass ConverterConvert grams, kilograms, ounces, pounds and stone in one bidirectional mass tool with exact avoirdupois factors, SI scaling and printable proof.Study & SchoolWeighted Average CalculatorCalculate a weighted mean from values and weights for grade categories, credits, survey scores, index components and spreadsheet checks, with contribution lines, total-weight warnings and a printable weighted-average worksheet record.Time & DateWork Hours CalculatorWork out paid hours from start time, finish time and unpaid break minutes.

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