Consumption and economy run in opposite directions
Liters per 100 kilometers measures fuel used over a fixed distance. Kilometers per liter and miles per gallon measure distance obtained from a fixed fuel volume. Moving between those directions requires a reciprocal, not a simple multiplier.
A lower L/100 km value means less fuel consumed, while a higher km/L or mpg value means more distance per unit of fuel.
US mpg and Imperial mpg are different
| Definition | Exact volume | Distance |
|---|---|---|
| US mpg | 1 US liquid gallon = 3.785411784 L | 1 international mile = 1.609344 km |
| Imperial mpg | 1 Imperial gallon = 4.54609 L | 1 international mile = 1.609344 km |
Zero and infinity are not hidden
Zero consumption corresponds mathematically to infinite economy. Zero economy corresponds to infinite consumption. CalcOS displays ∞ for those reciprocal limits instead of substituting an arbitrary large number or reporting a calculation error.
This is a unit conversion, not a mileage prediction
The converter does not estimate traffic, driving style, load, weather, vehicle condition, energy content, or real-world range. It only changes the representation of a supplied fuel-consumption or fuel-economy value.
Authoritative references: NIST Handbook 44 (2026), Appendix C and UK Weights and Measures Regulations 1976.