Formula
Fuel consumption = Fuel used ÷ Distance travelled × 100Direct answer
Fuel consumption in litres per 100 kilometres is fuel used divided by distance travelled, multiplied by 100. The U.S. Department of Energy likewise frames trip fuel use by dividing distance by the vehicle’s fuel economy; this page keeps the inputs observable and reports the inverse metric too.
Variables and formula
- Distance travelled: kilometres for the measured trip.
- Fuel used: litres consumed over that same trip.
Litres per 100 km = (Fuel used / Distance travelled) × 100
Reproducible example
A 500 km trip using 35 L gives (35 / 500) × 100 = 7 L/100 km. The same trip produces 500 / 35 = 14.29 km/L.
Interpretation
Compare results only when the trips use the same units and similar conditions. A highway trip, a short urban trip and a loaded trip can each be valid measurements without being directly comparable.
Assumptions and limitations
- Fuel and distance describe the same trip.
- This is a measured rate, not a cost, emissions or range forecast.
- Fuel-pump readings, temperature, speed and payload can affect observed results.
Common mistakes
- Mixing miles with kilometres.
- Using fuel added after a different trip.
- Reading a single trip as a long-term vehicle rating.
Assumptions
- Distance and fuel cover the same trip.
- The result is a measured rate, not a fuel-cost or emissions forecast.
Sources and methodology
CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.
- Energy Awareness Quiz; U.S. Department of Energy; accessed Jul 27, 2026