Fuel Cost Calculator
Fuel Cost Calculator
What your driving costs in fuel — per trip, per month, per kilometre and per year — with the cost split among passengers and, if you like, an electric car’s running cost beside it.
Fuel cost
40 km a trip, 22 trips a month, 15 km/l, fuel at $100 a litre; an electric car using 15 kWh/100 km at $8 a kWh
Fuel cost
- km/l
- kilometres per litre — the Indian convention; l/100 km is used in Europe and the Gulf
- kWh/100 km
- an electric car’s energy use, as its trip computer shows it
Worked example
40 km a trip, 22 trips a month, 15 km/l, fuel at $100 a litre; an electric car using 15 kWh/100 km at $8 a kWh
Fuel per trip = 40 ÷ 15 = 2.667 litres; cost $266.67
Per month = 266.67 × 22 = $5,867 (58.7 litres); per year $70,400
Per km = 100 ÷ 15 = $6.67
Electric: 15 ÷ 100 × 8 = $1.20 a km, $1,056 a month
Fuel cost at 100 a litre, 880 km a month (40 km × 22 trips)
| Fuel economy | Litres per 100 km | Cost per km | Cost a month |
|---|---|---|---|
| 8 km/l | 12.5 | $12.50 | $11,000 |
| 12 km/l | 8.3 | $8.33 | $7,333 |
| 15 km/l | 6.7 | $6.67 | $5,867 |
| 20 km/l | 5.0 | $5.00 | $4,400 |
| 25 km/l | 4.0 | $4.00 | $3,520 |
Getting the inputs right
Fuel cost is simple multiplication; what makes it right is the inputs. Fuel economy is the one to check. The figure in a brochure comes from a standard test cycle and is usually better than you will see in city traffic with the air-conditioning on. The honest number comes from your own fill-ups: fill the tank, note the odometer, and at the next fill-up divide the kilometres driven by the litres you put in. India quotes economy in km per litre; much of Europe and the Gulf quote litres per 100 km, which runs the other way — a lower number is better. The page takes either.
The two scales are reciprocals, so improvements are not what they seem. Going from 8 to 12 km/l saves $3,667 a month on the table’s 880 km; going from 20 to 25 km/l saves only $880. Litres per 100 km shows this directly, which is why engineers prefer it.
Electric comparison. Enter the car’s energy use in kWh per 100 km and what you pay per kWh to see its energy cost per kilometre. Home charging at a household tariff is usually far cheaper than a public fast charger, and charging losses mean the meter records somewhat more than the car’s display. Energy is only part of running a car: the purchase price, loan, insurance, servicing, tyres and resale value can outweigh it. For the loan side see the car loan EMI calculator and the car loan vs cash calculator; to fit the result into a monthly plan, the budget calculator. Fuel prices change often; the default price is only an example. This is arithmetic on the figures you enter, not financial advice.
Frequently asked questions
How do I calculate fuel cost for a trip?
Distance ÷ km per litre × price per litre. 40 km at 15 km/l and $100 a litre is 2.67 litres, $266.67.
How do I convert km/l to litres per 100 km?
Divide 100 by the km/l figure: 15 km/l is 6.7 litres per 100 km. The same division converts back.
How can I find my car’s real mileage?
Fill the tank, note the odometer, drive normally, and at the next fill-up divide the kilometres driven by the litres needed to fill it again.
Is an electric car cheaper to run?
Per kilometre, usually, when charged at home: 15 kWh/100 km at 8 a kWh is 1.20 a km. Public fast charging costs more, and the purchase price and insurance are not part of this comparison.
Related calculators
References
- Bureau of Energy Efficiency, Ministry of Power, Government of India. Corporate Average Fuel Efficiency (CAFE) norms for passenger cars, expressed in litres per 100 km and measured on a standard test cycle.
- U.S. Department of Energy and Environmental Protection Agency. fueleconomy.gov — “Your MPG will vary”: why real-world fuel economy differs from label values, and energy use of electric vehicles in kWh per 100 miles, including charging losses.
- International Energy Agency. Global EV Outlook: electric car energy consumption and charging.