What is the difference between UK and US MPG?

A UK gallon (4.546 L) is larger than a US gallon (3.785 L), so the same car shows a higher MPG in the UK. Pick the correct unit.

Fuel Cost Calculator — Journey & Trip Petrol Cost Calculator

Q: How do I calculate the fuel cost of a journey?

Fuel cost = (distance ÷ fuel economy) × fuel price. Enter distance, MPG or L/100km, and fuel price. It handles return trips and splitting between passengers.

Q: Where do I find my car's MPG?

In the handbook, the manufacturer's website, or the dashboard trip computer. Real-world economy is usually a bit lower than the official figure.

Q: Can I split the fuel cost with passengers?

Yes, enter the number of people in Split between and it shows the cost per person.

Our free fuel cost calculator works out how much petrol or diesel a journey will cost. Enter the distance, your car's MPG (miles per gallon) and the fuel price, and it instantly shows your total fuel cost — for a one-way trip or return, and split between passengers. The handy petrol cost calculator for commutes, road trips and expense claims.

Journey Details

Distance

Distance unit

Return trip?

Fuel economy

Economy unit

Fuel price

Price unit

Split between

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total fuel cost

Fuel Needed

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Cost per Person

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Cost per Mile

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❓ Frequently Asked Questions

How do I calculate the fuel cost of a journey? ▼

Fuel cost = (distance ÷ fuel economy) × fuel price. Enter your journey distance, your car's MPG or L/100km, and the price of fuel, and the calculator does the maths instantly — including return trips and splitting the cost between passengers.

Where do I find my car's MPG? ▼

Your car's official MPG is in its handbook or on the manufacturer's website. Many cars also display average MPG on the dashboard trip computer. Real-world economy is usually a bit lower than the official figure, so use your dashboard reading for the most accurate cost.

What's the difference between UK and US MPG? ▼

A UK gallon (4.546 litres) is larger than a US gallon (3.785 litres), so the same car shows a higher MPG figure in the UK than the US. Make sure you pick the right unit — our calculator supports UK MPG, US MPG, L/100km and km/L.

Can I split the fuel cost with passengers? ▼

Yes — enter the number of people sharing the journey in the "Split between" box and the calculator shows the cost per person. Great for car-sharing, lift money and splitting road trip costs fairly.