Free tool
MPG ↔ L/100 km Converter
Convert between US miles per gallon and litres per 100 kilometres in both directions. Useful because fuel economy is quoted in opposite directions on either side of the Atlantic — bigger is better in MPG, smaller is better in L/100 km.
Type in either box. The conversion constant is 235.214583 (100 km ÷ 1.609344 km/mi × 3.785411784 L/gal).
Common conversions
| US MPG | L/100 km | US MPG | L/100 km |
|---|---|---|---|
| 20 | 11.76 | 25 | 9.41 |
| 25 | 9.41 | 30 | 7.84 |
| 30 | 7.84 | 35 | 6.72 |
| 35 | 6.72 | 40 | 5.88 |
| 40 | 5.88 | 45 | 5.23 |
| 45 | 5.23 | 50 | 4.70 |
| 50 | 4.70 | 55 | 4.28 |
| 55 | 4.28 | 60 | 3.92 |
| 60 | 3.92 | 65 | 3.62 |
Frequently asked questions
Which MPG does this use?
US miles per gallon. Imperial (UK) gallons are about 20% larger, so UK MPG figures are not directly comparable.
Why is L/100 km better for comparing cars?
Because it is proportional to fuel consumed. Differences in L/100 km map linearly to fuel bought, whereas MPG does not.
How do I convert electric efficiency?
Electric cars are usually quoted in kWh per 100 miles or miles per kWh. The calculators on this site handle that directly.
Is the conversion exact?
Yes — it is a fixed constant, not an estimate.
Can I use this for diesel?
Yes, the unit conversion is fuel-agnostic.
Do you convert cost as well?
Not here — use the calculators, which price fuel and electricity directly.
Data sources. Vehicle efficiency: U.S. EPA / DOE fueleconomy.gov (2026 model year). Electricity prices: U.S. EIA Form 861M (residential, June 2026). Fuel prices: U.S. EIA weekly retail (week ending 2026-09-07). All figures are estimates, not quotes.