Petrol cost calculator: what will your journey cost?

Works for petrol or diesel, one-way or return. Uses the standard UK formula: miles ÷ MPG → gallons → litres × pump price.

How the maths works

Distance in miles divided by MPG gives gallons of fuel used. One UK gallon is 4.546 litres, so multiply gallons by 4.546 and then by the pump price per litre. A 100-mile trip at 50 MPG uses 9.1 litres, about £13.40 at 147p/litre.

Driving for work? The trip may be worth more than it costs

If you drive your own car on business journeys, HMRC's approved mileage rate is now 55p per mile (first 10,000 miles, 2026/27), the first rise in 15 years. A 100-mile business trip is a £55 claim against roughly £13 of fuel. The catch: HMRC expects a record of the date, route, purpose, and miles for every trip. Full guide to the 55p rate →