Fuel Cost Calculator
Fuel cost for a journey in any of the four efficiency units in common use, with the cost per kilometre and the split between passengers. Fuel is the visible cost of driving and usually not the largest one.
Also called: petrol cost calculator, trip fuel calculator.
$2,953.13 of fuel for 450 km at 28.13 litres, which is $6.56 a kilometre. At 6.56 a kilometre in fuel alone. Tolls, tyres, servicing and depreciation sit on top and usually exceed this. The car uses 6.25 litres per hundred kilometres, which is the unit that averages correctly across a mixed journey. Kilometres per litre is a reciprocal: two equal legs at 10 and 20 kmpl average 13.3, not 15.
If the price or the efficiency moved
| Scenario | Fuel cost | Change |
|---|---|---|
| -10% price, -10% efficiency | $2,953 | 0% |
| -10% price, +0% efficiency | $2,658 | -10% |
| -10% price, +10% efficiency | $2,416 | -18.2% |
| +0% price, -10% efficiency | $3,281 | 11.1% |
How this is calculated
Distance divided by efficiency gives the litres, and the rest is multiplication. The unit conversions are where the arithmetic gets fiddly: a US gallon is 3.785 litres and an imperial gallon 4.546, a difference of twenty percent, so a figure quoted in miles per gallon means materially different things on either side of the Atlantic. Internally everything converts to litres per hundred kilometres, which is linear in fuel consumed and can therefore be averaged, where kilometres per litre is a reciprocal and cannot: a car doing 10 and 20 kmpl on two equal legs averages 13.3 and not 15.
distance over efficiency gives litres, and litres times price gives the cost- d
- Distance
- e
- Kilometres a litre
- p
- Price a litre
Method and limits
What it assumes
- A steady efficiency across the journey, where real consumption varies with speed and load.
What it deliberately does not model
- Real-world efficiency falls well below the rated figure, particularly in city traffic and with air conditioning.
- This is fuel alone. Tolls, parking, tyres, servicing and depreciation are not included.
Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator
Frequently asked questions
- Why can I not average two kmpl figures?
- Because kilometres per litre is a reciprocal. Two equal legs at 10 and 20 kmpl average 13.3, not 15. Litres per hundred kilometres averages correctly because it is linear in fuel used.
- Is a US gallon the same as an imperial one?
- No. The imperial gallon is about twenty percent larger, so the same car is rated at a noticeably higher figure in the UK than in the US for identical consumption.