Fuel Cost Calculator
What a journey costs in fuel or in electricity, and the two compared when you give both.
Runs entirely in your browser. Nothing is uploaded, logged or stored.
Cost of the journey
60.12
- Fuel or electricity used
- 32.50 L
- Consumption per 100 km
- 6.50 L/100 km
- Cost per 100 km
- 12.02
- The same journey in the second
- Difference
How much a journey costs, from your consumption and your price. Fill in the second pair and it prices the same journey in another vehicle — which is the question most people are actually asking when they compare petrol with electric.
How it works
Everything is converted to litres — or kilowatt-hours — per hundred kilometres first, then multiplied by the distance and the price.
Miles per gallon and litres per hundred kilometres run in opposite directions: higher is better in one, lower in the other. The conversion between them is a reciprocal and not a factor, which is the classic error in a fuel calculator. 36.2 US mpg and 43.5 imperial mpg are both about 6.5 litres per hundred kilometres.
The two gallons are not the same volume either. An imperial gallon is 4.546 litres and a US gallon is 3.785, so the same car is about twenty per cent more economical in imperial figures without having changed at all.
Fuel and charging only. Depreciation, tyres, servicing, insurance and the price of the vehicle are not here, and for an honest comparison between two cars they matter as much as the fuel.
Examples
| Case | Input | Result |
|---|---|---|
| A long drive on petrol | 500 km, 6.5 L/100 km, 1.85 a litre | 32.5 litres — 60.12 |
| The same drive, electric | 500 km, 16 kWh/100 km, 0.25 a kWh | 80 kWh — 20.00 |
| The same car in three units | 6.5 L/100 km | 36.2 US mpg, 43.5 imperial mpg |
Frequently asked questions
Why are my miles per gallon so different from a US site?
Because the gallons differ. An imperial gallon is 4.546 litres and a US gallon is 3.785, so the same car reads about twenty per cent better in imperial figures. Pick the one your own figure came in.
Can I compare an electric car with a petrol one?
Yes — that is what the second pair of fields is for. Give the electric consumption in kilowatt-hours per hundred kilometres and its price per kilowatt-hour, and the same journey is priced both ways. Charging at home and charging at a motorway rapid charger are different prices, and the difference is often larger than the difference between the cars.
Does this include everything a car costs?
No, only the fuel or the electricity. Depreciation is usually the largest cost of running a car and it is not here, along with tyres, servicing and insurance. For a real comparison between two vehicles those matter as much as what goes in the tank.
Why is the consumption per 100 km shown as well?
Because a total depends on how far you drove, and the per-hundred figures are what actually compare two vehicles or two tariffs.
Good to know
- Manufacturers' consumption figures come from a standard test cycle and real driving is usually worse, often by ten to twenty per cent. Your own figure from a full tank divided by the distance is a better input than the brochure.