Fuel Cost Calculator

What a fuel cost calculator does

A fuel cost calculator estimates two things for any journey: how much fuel it will burn and what that fuel will cost. Give it a distance, your car's efficiency and the current fuel price and it does the rest — including doubling up for a round trip and dividing the bill when you're splitting with passengers.

It works in both metric (kilometres, litres per 100 km, price per litre) and imperial (miles, miles per gallon, price per gallon), and everything runs in your browser.

How the calculation works

Fuel used depends on which unit system you pick:

• Metric: litres used = distance ÷ 100 × (L/100 km). A 250 km trip at 7.5 L/100 km uses 250 ÷ 100 × 7.5 = 18.75 litres.
• Imperial: gallons used = distance ÷ mpg. A 150-mile trip at 32 mpg uses 150 ÷ 32 = 4.69 gallons.

The total cost is then fuel used × price. Tick round trip and the distance doubles first; set split between to divide the total by the number of people.

How to use it

1. Choose your unit system — Metric or Imperial. Every label updates to match.
2. Enter your trip distance.
3. Enter your fuel efficiency (L/100 km or mpg).
4. Enter the fuel price per litre or gallon, and pick a currency symbol for display.
5. Optionally tick round trip and set split between N people.
6. Read the total cost, plus fuel used and per person in the breakdown. Copy grabs a summary; Clear resets.

A worked example

You're driving 250 km each way to visit family, your car averages 7.5 L/100 km, fuel is €1.75 a litre, and there are 4 of you sharing:

• Round-trip distance: 250 × 2 = 500 km
• Fuel used: 500 ÷ 100 × 7.5 = 37.5 litres
• Total cost: 37.5 × €1.75 = €65.63
• Per person: €65.63 ÷ 4 = €16.41 each

Switch to Imperial and enter miles, mpg and price per gallon, and the same logic applies with gallons in place of litres.

A note on accuracy

This is an estimate. Real fuel use swings with driving style, traffic, weather, load, tyre pressure and terrain — a manufacturer's quoted efficiency is a lab figure that few of us match on a motorway with luggage and a headwind. Fuel prices also vary between stations and change often. Treat the result as a solid planning figure and add a little headroom for the tank.

To compare distances across units, the Unit Converter is useful, and for working out the percentage a fuel saving makes to a budget, try the Percentage Calculator. Browse everything on the all tools page.

Private by design

Nothing you type is uploaded or stored — the whole calculation runs locally in your browser with plain JavaScript. The currency button is for display only and doesn't change the maths, so you can use any currency you like.