Conversion family
Fuel Efficiency conversion calculators
Use fuel-efficiency conversions to compare vehicle economy across countries.
These 15 guides cover the most commonly searched unit pairs. Each page includes the exact relationship, worked values, and a reverse-conversion path.
How to use fuel efficiency conversions
Choose the guide whose source unit matches the value you already have and whose target unit matches the format you need. Enter the value without rounding it first, review the displayed relationship, and round only the final answer to the precision your task requires. Popular starting points in this family include Gallons Per 100 Miles to Miles Per Gallon, Imperial Miles Per Gallon to Kilometers Per Liter, Imperial Miles Per Gallon to Liters Per 100 Kilometers.
Fuel-consumption units do not all increase in the same direction. Higher miles per gallon means better efficiency, while lower liters per 100 kilometers means better efficiency, so conversions between them use an inverse relationship rather than one fixed multiplier. Unit symbols can be case-sensitive, and similarly named units may belong to different systems, so check the label as well as the abbreviation before relying on the result.
- Keep the original value at full precision until the final step.
- Confirm the unit symbol, system, and measurement type.
- Use the reverse guide to check that the result returns to the starting value.
Measurement context
Confirm the measurement type before converting
Exact unit factors work best when the source and target units describe the same kind of measurement and the source convention is clear.
- Check the unit symbol, full unit name, and measurement family before entering a value.
- Keep the original number unrounded until the final result.
- Use the reverse guide or a known reference value to sanity-check important results.