Fuel Cost Calculator
Find out what a journey will cost in fuel. Works with miles or kilometres, any fuel economy unit, and per-person splits.
How to calculate fuel cost for a trip
- Enter the distance and choose miles or kilometres. Tick Round trip to double it.
- Enter your vehicle’s fuel efficiency in mpg, L/100 km or km/L, and the fuel price per litre or gallon.
- Read the fuel needed, total cost and cost per person, plus the CO₂ produced.
Features
Any units
Miles or km, mpg (US or UK), L/100 km, km/L, litres or gallons.
Split the cost
Cost per person for shared journeys.
CO₂ estimate
Emissions for petrol or diesel.
Private
Everything is calculated in your browser; nothing is sent anywhere.
Frequently asked questions
How do I calculate fuel cost?
Fuel used = distance × consumption per distance, and cost = fuel used × price per unit. For 250 km at 7.5 L/100 km you use 18.75 L, which at 1.80 per litre costs 33.75.
What is the difference between US and UK mpg?
A UK (imperial) gallon is about 20% larger than a US gallon (4.546 vs 3.785 litres), so the same car shows a higher mpg figure in UK units. Choose the unit your car’s figure is quoted in.
How accurate is the estimate?
It uses a constant fuel economy. Real consumption varies with speed, load, traffic, terrain and weather, so add a margin for long or mountainous trips.
How is the CO₂ figure calculated?
It multiplies litres burned by about 2.31 kg of CO₂ per litre of petrol or 2.68 kg per litre of diesel, which are standard emission factors.