CalculationTime

MPG Calculator

Live math canvas

Your numbers, formula and explanation together

MPG Calculator: 26.6667 mpg. 3.75 gal/100mi · trip cost $45 · planned 18.75 gal for 500 mi

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.
  1. Apply the formulaMPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.26.6667 mpg3.75 gal/100mi · trip cost $45 · planned 18.75 gal for 500 mi

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Miles driven
320 mi
Enter the trip distance or odometer difference in miles.
Fuel used
12 US gal
Enter fuel used in US gallons. Use litres-to-gallons first if your receipt is in litres.
Fuel price
3.75 per US gal
Optional price per gallon for a trip cost and reimbursement note.
Planned distance
500 mi
Optional future distance for an estimated fuel and cost projection.
MPG rounding increment
0.1 mpg
Use 0.1 mpg for ordinary fuel logs or 0.01 for worksheets.

Resulting answer

26.6667 mpg

3.75 gal/100mi · trip cost $45 · planned 18.75 gal for 500 mi

Answer
26.6667 mpg
Live support
3.75 gal/100mi · trip cost $45 · planned 18.75 gal for 500 mi

Assumptions used

What this answer assumes

Best for road-trip planning, fuel receipts, fleet logs, mileage reimbursement notes, personal car comparisons and classroom unit-rate worksheets where the distance, gallons and price need to stay visible.

  • Fuel volume is treated as US liquid gallons, not imperial gallons or litres.
  • Distance is entered in statute miles from an odometer, map distance or trip log.
  • The result describes observed fuel economy for the entered trip; weather, traffic, tyre pressure, load, fuel blend, terrain and driving style can change real-world MPG.
  • Fuel price is optional planning arithmetic before taxes, discounts, reimbursement rules, card fees or fleet accounting adjustments.
  • For official fuel-economy labels, emissions reporting, tax records or employer reimbursement, use the required official method and keep original receipts.

Master’s Tip

How to use the result well

Master’s Tip: print the odometer start/end or receipt note beside the result. MPG is only useful when the distance and gallons came from the same trip window, not from a partial fill or mixed record.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Miles driven
320 mi
Enter the trip distance or odometer difference in miles.
Fuel used
12 US gal
Enter fuel used in US gallons. Use litres-to-gallons first if your receipt is in litres.
Fuel price
3.75 per US gal
Optional price per gallon for a trip cost and reimbursement note.
Planned distance
500 mi
Optional future distance for an estimated fuel and cost projection.

Embeddable calculator

Embed this calculator

Copy a clean iframe version with the required CalculationTime attribution link built in.

Direct answer

MPG Calculator in one sentence

An MPG calculator divides miles driven by US gallons used. This page also shows gallons per 100 miles, trip cost, estimated fuel for a planned distance and a printable mileage record so receipts, odometer notes and classroom examples stay auditable.

How to use this calculator

  1. Enter miles driven, fuel used, fuel price, planned distance and the remaining visible inputs.
  2. Check the formula, assumptions and worked example before reusing the number.
  3. Use the result, related calculators and printable record as the next practical step.

Default result preview

Fuel economy: 26.6667 mpg

This pre-calculated state lets readers and answer engines verify what the tool returns before the inputs change.

Show the working

MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.

The default inputs, formula and result stay together so the number can be checked or quoted without losing context.

Export this result

Copy the default solved state as Markdown or CSV, then print the page for a clean formula and result record.

Print or save report: use the browser print command to save the visible formula, result, assumptions and source context as a clean PDF.

How to prompt AI with this result

Copy this prompt with your final CalculationTime result when you want a second-pass explanation, comparison or next-step checklist.

Use this CalculationTime result as the source: MPG Calculator. Default output: Fuel economy = 26.6667 mpg. Formula/method: MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.. Explain the result, state the assumptions, and suggest the next calculation to check.
Formula

MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.

Worked example

For 320 miles and 12 US gallons, MPG = 320 ÷ 12 = 26.6667 mpg. Gallons per 100 miles = 12 ÷ 320 × 100 = 3.75 gal/100 mi. At $3.75 per gallon, the trip fuel cost is 12 × 3.75 = $45.00.

Professional note

Master’s Tip: print the odometer start/end or receipt note beside the result. MPG is only useful when the distance and gallons came from the same trip window, not from a partial fill or mixed record.

Regional and unit assumptions

Standard or basis: US miles per US liquid gallon. One US liquid gallon is 231 cubic inches, and MPG differs from litres per 100 kilometres and imperial miles per gallon.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.

Standard or basis

Standard or basis: US miles per US liquid gallon. One US liquid gallon is 231 cubic inches, and MPG differs from litres per 100 kilometres and imperial miles per gallon.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: print the odometer start/end or receipt note beside the result. MPG is only useful when the distance and gallons came from the same trip window, not from a partial fill or mixed record.

Authority & freshness

Who checked this calculator?

Page structure checked: 2026-09-26. Calculator-specific statutory or source-table dates appear in the revision log when the tool depends on time-sensitive rules.

Published by CalculationTime

CalculationTime publishes calculator pages with visible formulas, assumptions, worked examples, related next steps and printable records so the result can be audited instead of treated as a black box.

Machine-readable formula

MPG = miles driven ÷ US gallons used. Gallons per 100 miles = gallons used ÷ miles driven × 100. Trip fuel cost = gallons used × fuel price per gallon. Planned gallons = planned miles ÷ MPG.Formula text is also exposed in the page schema and visible methodology block.

Source basis

3 source references are attached to this page.

Related calculators

These cards are resolved from calculator data, category context and live-route status so the page links to useful next steps without hand-built link clutter.

Finance & MoneyFuel Cost CalculatorEstimate trip fuel cost from distance, fuel economy, fuel price and optional tolls or parking, with litres and gallons shown clearly.Open calculatorMeasurement & 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.Open calculatorMeasurement & Unit ConversionLength ConverterConvert millimetres, centimetres, metres, inches, feet, yards, kilometres and miles in one bidirectional length tool with the exact unit basis visible.Open calculatorDate & TimeSpeed CalculatorCalculate speed from distance and time, with miles per hour, kilometres per hour, metres per second and pace shown.Open calculatorMeasurement & 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.Open calculatorMeasurement & Unit ConversionTemperature ConverterConvert Celsius, Fahrenheit and Kelvin in one bidirectional temperature tool with offset formulas, absolute-zero guardrails and printable proof.Open calculator

Knowledge check

Test your understanding

Use these quick checks to confirm that the result, formula and assumptions make sense before you reuse the number.

Which inputs drive the default result?

The default result starts with Miles driven, Fuel used, Fuel price. The current pre-solved output is fuel economy = 26.6667 mpg.

Where is the calculation proof?

The proof is in the formula, worked example and assumptions sections. Together they show the arithmetic, the default state and the limits of the result.

What should you do after reading the answer?

Use the related calculators, printable record or source notes to check the next practical step instead of treating one output as the end of the workflow.

Accuracy feedback

Did this calculator work accurately?

This lightweight check records your answer in this browser only. It does not send personal data and does not claim a live backend review queue.

Report this calculation issue

Questions

How do I calculate MPG?

Divide miles driven by US gallons used. For example, 320 miles ÷ 12 gallons = 26.67 mpg.

What is gallons per 100 miles?

Gallons per 100 miles shows fuel consumed over a fixed distance. It is calculated as gallons used ÷ miles driven × 100, so lower is better.

Why is my calculated MPG different from the car sticker?

Sticker or official ratings use controlled test procedures. Your trip MPG can change with traffic, speed, load, weather, terrain, tyres, fuel blend and measurement quality.

Can I use litres in this MPG calculator?

This page expects US gallons. Convert litres to US gallons first, or use a litres-per-100-kilometres calculator when working entirely in metric units.

What should I print for a mileage record?

Print miles driven, gallons used, fuel price, MPG, gallons per 100 miles, trip cost, planned fuel estimate, formula, assumptions, page URL, date and notes from the receipt or odometer log.

Calculation note

Miles per gallon is a unit-rate record: how far a vehicle travelled for each US gallon of fuel. It is familiar in the United States, while many other countries use litres per 100 kilometres, a consumption measure where lower values are better.

MPG is a distance-per-fuel rate

The calculation divides distance by fuel volume, so a larger MPG means more miles from each gallon. The inverse view, gallons per 100 miles, can make fuel consumption and cost comparisons easier.

Trip records need matched inputs

A trustworthy MPG note uses miles and fuel from the same period. Partial fills, forgotten odometer readings or mixed city/highway trips can explain surprising results.

Printable mileage notes support real decisions

A filed report with distance, gallons, price and assumptions is useful for road-trip budgets, reimbursement conversations, fleet checks and student unit-rate exercises.

Sources and further readingU.S. Department of Energy and EPA — FuelEconomy.govEPA — Fuel economy label and rating informationNIST Handbook 44 Appendix C — General Tables of Units of Measurement