Fuel Cost Calculator
Enter fuel amount and distance to calculate consumption (L/100km), cost per kilometer and total trip cost. Includes range estimation. Runs locally.
Updated July 11, 2026
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How to use
- 1
Enter fuel used and distance traveled.
- 2
Enter fuel price per liter.
- 3
See consumption, cost and range estimates.
How it works
Why L/100km and mpg look like opposites
Metric L/100km is consumption — fuel used per fixed distance. Lower is better. U.S. mpg (miles per gallon) is efficiency — distance per fixed amount of fuel. Higher is better.
Because one measures fuel-per-distance and the other distance-per-fuel, the relationship is not linear — it is a hyperbola. The conversion factor between them is fixed at 235.215: divide it by either number to get the other. This also means each mpg improvement saves less fuel at the high end — going from 10 to 20 mpg saves far more fuel than going from 40 to 50 mpg over the same distance.
- L/100km → mpg: mpg ≈ 235.215 ÷ L/100km
- mpg → L/100km: L/100km ≈ 235.215 ÷ mpg
- Real-world consumption typically runs 15–25% above official WLTP or EPA figures
How this is calculated
- Formula:
- Fuel cost = distance ÷ efficiency × price per unit. Metric: cost = (distance km ÷ 100) × (L/100km) × price/L. U.S.: cost = distance miles ÷ mpg × price/gallon. L/100km → mpg: mpg ≈ 235.215 ÷ (L/100km).
- Applies to:
- Reference rates; confirm fuel prices in your market.
Real consumption depends on driving style, terrain, speed, load, tyre pressure, and weather — quoted efficiency figures are laboratory estimates (e.g. WLTP, EPA) that real-world driving rarely matches. Results are estimates for comparison only; not financial advice. Verify current fuel prices at the pump or with your supplier.