Fuel Cost Calculator
Estimate fuel cost for a trip from distance, fuel consumption and petrol price per litre, free and instant right in your browser.
Trip & fuel
Trip cost
Enter distance, fuel economy and price to see the cost.
The $ symbol is for display — the maths works for any currency. Switch Metric / US / UK to enter km & L/100km or miles & MPG (US and UK gallons differ). Calculations run in your browser.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Pick your units: Metric (km, L/100km), US (miles, MPG) or UK (miles, MPG).
- Enter the distance, your fuel economy and the fuel price.
- Tick Return trip to double the distance. Read off the fuel used and trip cost instantly.
How it works
Metric: litres = distance ÷ 100 × (L/100km), then × price per litre for the cost.
US/UK: gallons = miles ÷ MPG, then × price per gallon. A US gallon (3.785 L) is smaller than a UK gallon (4.546 L), so the same MPG figure means different real economy — the tool keeps them separate.
It also shows cost per 100 km, a region-neutral figure handy for comparing vehicles.
Worked example
500 km at 10 L/100km, $2/L. Fuel = 50 L, cost = $100. The same trip at 30 MPG (US) and $3.50/gal would show in US units instead.
Frequently asked questions
Where do I find my fuel economy?
Check the car's specs, or work it out: litres used ÷ km driven × 100 (metric), or miles driven ÷ gallons used (MPG).
Why are US and UK MPG different?
A US gallon is about 3.785 litres and a UK (imperial) gallon is about 4.546 litres, so a UK MPG number is roughly 20% higher than the US one for the same real economy. Choose the matching region so the price-per-gallon lines up.
Does it work in my currency?
Yes — the $ is only for display. Enter the price in your own currency and every result is in that currency.
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Cite this tool
Zerdly. (2026). Fuel Cost Calculator. Retrieved from https://www.zerdly.com/tools/fuel-cost-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.