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Fuel & mileage

Fuel Cost Calculator

Calculate trip fuel cost and split costs in U.S., metric, or UK units, including Imperial MPG and pounds per litre.

By AutomotiveCalc · Published September 9, 2026
How this calculator is checked

Automated checks cover formula examples and input validation. This page has not received an independent automotive professional review.

Sources & calculation method · Review standards · Report a problem

Your numbers

Example calculation

Example results are shown below. Controls become available when the calculator loads.

Choose your measurement system and currency before entering prices. Changing a selection reinterprets the numbers; it does not convert units or exchange currencies. With GBP selected, enter pounds per litre, not pence (150p = £1.50).

Trip fuel cost$35.00
Fuel needed10 U.S. gal
Cost per person$35.00
Cost per mile$0.12

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How to use this calculator

Replace the example values with your own measurements or specifications. Keep the units shown beside each label. Results update as you type; reset restores the example.

Enter the total distance, including the return leg if needed. This estimate excludes tolls, parking, wear, and lodging. Use your measured mileage for a more realistic estimate; weather, speed, and traffic can change consumption.

The formula

U.S.: gallons = miles ÷ U.S. mpg. Metric: liters = kilometers × L/100 km ÷ 100. Fuel cost = fuel volume × price per matching unit. Cost per person = trip cost ÷ people. Cost per distance = consumption per mile or km × fuel price. UK: litres = miles ÷ Imperial mpg × 4.54609. Cost = litres × price per litre.

A worked example

U.S. example: 300 miles at 30 mpg uses 10 gallons and costs $35 at $3.50/gallon. Metric example: 500 km at 8 L/100 km uses 40 liters. At $1.60/liter, the trip costs $64, or $32 each for two people. UK example: 300 miles at 40 Imperial mpg uses 34.10 litres. At £1.50/litre, the fuel costs £51.14.

Common questions

Is the default gas price current?

No. It is an example, not a live fuel price. Replace it with the price at your station.

Should I use highway or combined MPG?

Use the value that best matches your trip, or measured mileage from similar driving.

Can I enter kilometers and liters?

Yes. Choose Metric, then enter distance in km, consumption in L/100 km, and price per liter. Use the fuel-economy converter if your vehicle figure is in MPG or km/L.

Does switching systems convert my inputs?

No. It changes which units describe your inputs. Replace the numbers with readings in the selected system.

Can I calculate UK petrol or diesel costs?

Choose UK and GBP. Enter miles, Imperial MPG, and pounds per litre. Do not mix U.S. MPG with Imperial MPG or enter pence as pounds.

Does selecting GBP or EUR apply an exchange rate?

No. Currency selection labels and formats the amount only. Enter your actual pump price in that currency.

Sources & calculation method

Related guidance: U.S. DOE / EPA: fuel economy and driving. Accessed September 9, 2026. The equation above describes this tool’s model; the reference provides practical context and does not endorse this site.

Formula examples and input validation have automated checks. This page has not received an independent automotive professional review. Read our review standards.