CalculationTime

All tools

Type what you want to work out, or find the calculator for it.

Work it out here

Scientific keys, or a quick sum with a few everyday conversions under the answer.

About this clockface

On this page

DeskAsk a sum in wordsType a sum in words, like 20% off 150 or 30 C in F, on this page.

Time: clock time and hours worked

CalculatorDecimal Hours to Hours & Minutes7.75 hours is 7 h 45 min. Convert timesheet hours either way.CalculatorTime CalculatorAdd or subtract lengths of time and see them in days, hours and minutes.CalculatorTime Unit ConverterSeconds, minutes, hours, days and weeks.

Time: timers and stopwatches

CalculatorOnline StopwatchStart, stop and lap, with a printable record.CalculatorCountdown TimerA 1 to 60 minute timer with a chime, or the days to any date.

Time: dates and countdowns

CalculatorDays Between Dates CalculatorDays, weeks and workdays from one date to another.CalculatorAge CalculatorExact age in years, months and days on any date.

Time: time zones

CalculatorTime Zone Meeting PlannerUp to 8 cities, everyone's working hours and the kindest time to meet.

Time: sun, Moon and sky time

CalculatorSunrise and Sunset CalculatorSunrise, sunset, golden hour and twilight for any place.CalculatorMoon Phase CalculatorHow much of the Moon is lit tonight, and when it is full.CalculatorSeasons and Solstices CalculatorThe next equinox or solstice in your own time.CalculatorEclipse CalculatorThe next eclipses and where they can be seen.InstrumentCalculation Time ClockA clock with the Southern Cross as its fourth hand.CalculatorSouthern Cross Time and Date CalculatorThe hour from the date, or the date from the hour, by the Hand of the Cross.InstrumentThe Wanderers' LaneThe Sun, Moon and planets on one moving road.InstrumentThe Grand OrreryThe Solar System in 3D, and where each planet is tonight.InstrumentThe Spiral Grand OrreryThe planets following the Sun through the galaxy.

Money: borrowing and home loans

CalculatorMortgage CalculatorMonthly repayments, interest and the payoff date.CalculatorLoan CalculatorRepayments and total interest on any fixed loan.

Money: saving and growing money

CalculatorCompound Interest CalculatorHow savings grow when interest earns interest.CalculatorInflation CalculatorWhat money from any year since 1913 is worth today, from the official price index.

Money: business and trade

CalculatorCurrency ConverterToday’s ECB rate for 30 currencies, and what a bank margin costs.

Maths: everyday maths

CalculatorPercent CalculatorPercent of, percent change and reverse percent.CalculatorAverage CalculatorMean, median, mode and range of a list.

Maths: shapes and measurement

CalculatorArea CalculatorArea of rectangles, circles, triangles and more.CalculatorVolume CalculatorVolume of a box, cylinder, sphere, cone or ring.

Maths: converting units

CalculatorMetres to Feet and InchesA height or length in feet and inches, to the nearest fraction.CalculatorWeight and Mass ConverterKilograms, pounds, stone and ounces.CalculatorTemperature ConverterCelsius, Fahrenheit and kelvin.CalculatorSpeed ConverterMiles per hour, kilometres per hour, knots and metres per second.CalculatorLand Area ConverterHectares, acres and square metres.CalculatorCooking Volume ConverterCups, spoons and millilitres, with US, UK and Australian cups.

Maths: sound and pattern

CalculatorCymatics CalculatorThe pattern a frequency makes, its note, and intervals in cents.

Maths: calculators

CalculatorScientific CalculatorTrig, logs, powers and memory.

Flooring: floors

CalculatorProfessional Flooring CalculatorRoll goods, planks and tiles with waste and a quote list.

Flooring: measuring up

One of a kind on CalculationTime

The Grand OrreryWhere every planet is on any date from 1700 to 2200, and what is up tonight.Southern Cross ClockRead the Southern Cross like a clock, and see where its hand points tonight.Earth ClocksWatch the Earth turn beneath the Sun, a clock on each of the 24 time zones.

Ask a sum in words

Type it the way you would say it: 15% of 80, 5 ft 7 in in cm, days until 25 December.

Your answer

Ask it the way you would say it

Type a sum, a percentage, a conversion or a date question, and the answer and its working appear here.

Getting a straight answer from the box

Write the question the way you would say it. “20% off 150” gives 120, “150 + 20%” gives 180, and “20% of 150” gives 30: three different questions that people often mix up, so the box shows its working each time. Brackets are worked first, so “(12 + 8) × 7.5” is 150, while “12 + 8 × 7.5” is 72.

For a conversion, put the units in: “5 ft 7 in in cm” or “30 C in F”. For a date, name the day: “days until 25 December” counts from today where you are, and “what day is 1 May 2027” gives the weekday.

When a question needs more than one line, such as a loan with fees or the hours in a week of shifts, the box names the calculator that handles it.