Fuel Converter

Fuel economy converter: MPG, L/100 km, and km/L

Fuel economy labels invert intuition depending on country. US window stickers show miles per gallon (higher is better). European ads quote liters per 100 kilometers (lower is better). Canadian brochures may use kilometers per liter.

Convert before comparing hybrids, imports, or fleet spreadsheets—mental math inverts easily and ranks the wrong car as “more efficient.”

How to use this converter

1. Pick the economy unit on the sticker or advertisement.
2. Enter the value.
3. Select the unit your audience understands.
4. Compare vehicles on equal footing.

Before and after examples

Same efficiency, different labels.

Why MPG and L/100 km feel backwards

MPG measures distance per volume: more miles per gallon means better economy. L/100 km measures volume per distance: fewer liters per 100 km means better economy. Doubling MPG is not the same as halving L/100 km—the relationship is nonlinear.

Use a converter instead of memorizing reciprocals. A jump from 30 to 40 MPG is a smaller savings than 10 to 20 MPG even though both are “+10 MPG.”

US MPG vs imperial MPG

UK imperial gallons are larger than US gallons, so imperial MPG numbers look higher for the same car. Always note which gallon the brochure uses before bragging about efficiency.

Fleet, emissions, and reporting

Corporate sustainability reports may require L/100 km or g CO₂/km while drivers track US MPG. Normalize units quarterly so dashboards do not mix scales. EPA and WLTP test cycles also differ—unit conversion does not make ratings interchangeable.

Frequently asked questions