Fuel Cost Calculator
Work out how much fuel a journey will use and what it will cost.
Journey fuel cost
£17.58
- Fuel used
- 12.12 litres
- Cost per mile
- £0.15
Uses UK gallons (4.546 litres). Enter the pence-per-litre price shown on the pump.
v1.0 · Reviewed September 2026
How this is worked out
Gallons used is miles ÷ MPG. That is converted to litres at 4.54609 litres per UK gallon and multiplied by the pump price in pence, then divided by 100 to give pounds.
Worked example
- 120 miles
- 45 MPG
- 145p per litre
120 ÷ 45 = 2.667 gallons = 12.12 litres, × 145p
£17.58, about 15p a mile
Assumptions and limits
- Uses the UK imperial gallon of 4.54609 litres. A US gallon is 3.785 litres, so American MPG figures are not comparable.
- Assumes the MPG you enter holds for the whole journey. Official figures are usually optimistic, and cold, urban or motorway-speed driving all change consumption.