Fuel Economy Unit Converter

Why higher isn't always better across these units

Fuel economy units aren't just different numbers for the same idea - MPG and km/L measure distance per fuel unit (higher is better), while L/100km measures fuel used per fixed distance (lower is better), a genuinely inverse relationship that trips up cross-market comparisons.

Worked example

For 30 MPG (US):

Result = 30.0 MPG (US) = 7.84 L/100km = 12.754 km/L

Frequently asked questions

Why does the US use MPG while most other countries use L/100km? Historical convention mainly - both units describe the same physical quantity (fuel efficiency), just expressed with distance or fuel volume as the fixed reference amount, which is why direct conversion always requires this reciprocal-style calculation rather than a simple linear scale factor.

Is UK MPG the same as US MPG? No - Imperial gallons (used in UK MPG figures) are larger than US gallons, so a UK MPG rating is not directly comparable to a US MPG rating without an additional conversion factor. This calculator uses US gallon-based MPG only.