Three tools in one: calculate your car's fuel consumption from a fill-up, estimate the total fuel cost of any trip, or convert between L/100km, MPG (UK), MPG (US) and km/L. Instant results, no sign-up required.
Choose the mode that matches your need. Calculate mode takes the fuel used (in litres) and distance covered (in km) from a real fill-up or trip — ideal for measuring your car's actual economy. It outputs L/100km, km/L, MPG (UK) and MPG (US) all at once. Trip Cost mode lets you plan ahead: enter a distance, your car's consumption rate and the current fuel price to get the total fuel cost and litres needed. Convert mode translates between any two fuel economy units.
L/100km (litres per 100 kilometres) is the standard metric used in Europe, Australia and most of the world. Lower is better — a 6 L/100km car is more efficient than a 9 L/100km car. MPG (miles per gallon) is used in the UK and USA — higher is better. Note that UK MPG and US MPG use different gallon sizes, so a UK rating of 40 MPG is only equivalent to 33 MPG in US terms.
km/L (kilometres per litre) is used in Japan, India and parts of Latin America — higher is better, like MPG. All four units express the same underlying relationship between distance and fuel; they just invert and scale differently.
The conversion constants (282.48 and 235.21) derive from the number of kilometres in a mile (1.60934) multiplied by the litres in a UK gallon (4.54609) or US gallon (3.78541) respectively.
| L/100km | MPG (UK) | MPG (US) | km/L | Typical Vehicle |
|---|---|---|---|---|
| 4.0 | 70.6 | 58.8 | 25.0 | Hybrid / EV range-extender |
| 5.0 | 56.5 | 47.0 | 20.0 | Small efficient petrol |
| 6.0 | 47.1 | 39.2 | 16.7 | Economy saloon |
| 7.5 | 37.7 | 31.4 | 13.3 | Average family car |
| 9.0 | 31.4 | 26.1 | 11.1 | SUV / larger petrol |
| 12.0 | 23.5 | 19.6 | 8.3 | Large SUV / pick-up truck |
| 15.0 | 18.8 | 15.7 | 6.7 | High-performance / older diesel |
Results from this calculator are estimates based on standard fuel-efficiency conversion formulas (L/100km ↔ MPG) and are provided for general informational purposes. Rounding, regional standards and manufacturer variations can cause small differences from official or brand-specific figures.
For decisions where precision is critical — engineering, construction or legal contexts — verify results with a qualified professional or an official reference source.
This calculator uses standard fuel-efficiency conversion formulas (L/100km ↔ MPG). The underlying logic was built and manually cross-checked against independent reference calculators and textbook worked examples across dozens of test cases before publication.
Every formula on elCalculador is reviewed by our editorial team for mathematical accuracy, and pages are re-audited whenever a calculator's logic or inputs are updated.