Everyday
Fuel cost calculator
Estimate how much fuel a trip will use and what it will cost, with optional split across passengers. Pick metric (km / L / L per 100 km) or US (miles / gallons / mpg).
Formula
Two ways to express car efficiency: liters per 100 km (lower is better — used everywhere except the US and UK) and miles per gallon (higher is better — US and informally UK). They convert via 1 mpg ≈ 235.215 / (L/100km). A 25 mpg car ≈ 9.4 L/100 km.
The math is the same either way: amount of fuel = distance × efficiency factor (or distance ÷ efficiency in mpg), and cost = amount of fuel × price per unit.
This calculator ignores warm-up cycles, terrain, air conditioning, traffic, and load — real-world consumption can be 10–30% higher than the rated figure. For long-distance trips on flat highways at a steady 90 km/h, the rated number is usually close. For city driving in traffic, add 20%.
Examples
- 01500 km, 7 L/100km, $1.80/L, 2 people→ Fuel 35 L · Total $63.00 · Per person $31.50 · $0.126/km
- 02300 mi, 28 mpg, $3.50/gal, solo→ Fuel 10.71 gal · Total $37.50 · $0.125/mi
- 031000 km road trip, 6 L/100km diesel, $1.60/L→ Fuel 60 L · Total $96.00 · $0.096/km
FAQ
- L/100km = 235.215 / mpg, and mpg = 235.215 / (L/100km). So 30 mpg ≈ 7.84 L/100km, and 5 L/100km ≈ 47 mpg.