Finance

Fuel Cost Calculator

Free fuel cost calculator. Estimate the cost of gas for a road trip from distance, fuel efficiency (MPG or L/100km), and fuel price. Works with miles or kilometers, gallons or liters.

YOUR WORKSPACEFree to use. No sign-up.

Distance

Distance unit

Fuel efficiency

Efficiency unit

Fuel price

Price unit

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Enter your trip details above.

Deep dive guides

A LITTLE CONTEXT · 3 MIN READWhat a Trip Really Costs in Fuel

All 6 related guides

Fuel Cost Calculation: How to Estimate the Cost of a Trip — The simple fuel-cost formula (distance / efficiency × price), why mpg divides instead of multiplies, unit conversions, and multi-stop trips.
Energy Units Explained: Joules, kWh, BTU and Your Electricity Bill — Joules, kWh, BTU, and calories are one quantity at different scales — the exchange rates, the bill math, and which unit fits which job.
Electricity and Fuel: Where Your Running Costs Come From — The usage × price formula behind electricity and fuel running costs: kilowatt-hours, mpg in the denominator, cost per hour, cost per mile, and where savings hide.
BTU by the Numbers: Sizing Heating and Cooling for One Room — The 20 BTU per square foot rule, its correction factors for sun, insulation, and people, and why oversized air conditioners misbehave.
What a Trip Really Costs in Fuel — The three-input fuel cost calculation, how mixed metric and imperial inputs are normalized, and how to stretch the result into round trips and per-passenger costs.
How to Measure Fuel Economy: The Fill-Up Method Behind MPG and L/100km — Why fuel economy can only be measured between two full fill-ups, and how the MPG, km/L and L/100km unit families relate.

How fuel cost calculator works

This calculator estimates how much you will spend on fuel for a trip from three inputs: the trip distance, your vehicle fuel efficiency, and the fuel price per gallon or liter.

It normalizes units behind the scenes. Distance is converted between miles and kilometers (1 mile = 1.609344 km) and fuel volume between gallons and liters (1 gallon = 3.78541 liters). For MPG, fuel used is distance ÷ MPG; for L/100km, fuel used is distance × efficiency ÷ 100. The cost is fuel used × fuel price in the matching unit.

The result shows the total cost plus the fuel used in both gallons and liters and the distance in both miles and kilometers, so you can sanity-check the numbers regardless of which units you entered.

Frequently asked questions

How do I calculate fuel cost for a trip?

Multiply the trip distance by your fuel price per unit, then divide by your fuel efficiency. For MPG: cost = (distance ÷ MPG) × price per gallon. This calculator does that for you and handles unit conversions.

Can I use L/100km instead of MPG?

Yes. Set efficiency to L/100km and enter the distance in kilometers. Fuel used = distance × L/100km ÷ 100, then multiply by the price per liter.

Does it handle kilometers and liters?

Yes. Choose kilometers for distance, L/100km for efficiency, and per-liter for price — or mix any combination and the converter handles the unit math.

Why is my real-world cost higher?

Real fuel use varies with speed, traffic, load, air conditioning, and terrain. This calculator gives a planning estimate from steady-state efficiency; add a 10–15% buffer for city driving or heavy loads.

Fuel Cost Calculator

Deep dive guides

How fuel cost calculator works

Frequently asked questions

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