Convert MPG (US) to L/100km instantly — enter a value in either field.
| MPG (US) (mpg (US)) | L/100km (L/100km) |
|---|---|
| 15 mpg (US) | 15.7 L/100km |
| 20 mpg (US) | 11.8 L/100km |
| 25 mpg (US) | 9.4 L/100km |
| 30 mpg (US) | 7.8 L/100km |
| 35 mpg (US) | 6.7 L/100km |
| 40 mpg (US) | 5.9 L/100km |
| 45 mpg (US) | 5.2 L/100km |
| 50 mpg (US) | 4.7 L/100km |
| 55 mpg (US) | 4.3 L/100km |
| 60 mpg (US) | 3.9 L/100km |
Example: 30 mpg (US) → 235.215 ÷ 30 = 7.8 L/100km
MPG figures in the United States decrease as cars become more thirsty: a 15-mpg truck burns twice as much fuel as a 30-mpg sedan. The L/100km scale used in Europe reverses this relationship — lower L/100km is always better. Converting requires inversion: L/100km = 235.215 ÷ mpg (US).
Because the conversion is a reciprocal, small changes in mpg at low values translate to large swings in L/100km. Going from 15 to 16 mpg saves 3.3 L every 100 km, while going from 45 to 46 mpg saves only 0.5 L. This asymmetry is one reason European policymakers prefer L/100km — it makes the real-world fuel saving from efficiency improvements more visually obvious.
This formula assumes US gallons. The imperial gallon used in the United Kingdom is about 20% larger (4.54609 L vs 3.785 L), so British mpg figures need the constant 282.481 for accurate conversion to L/100km.
Divide 235.215 by 30 to get 7.8 L/100km. The formula is L/100km = 235.215 ÷ mpg (US).
Both measure the same efficiency from opposite directions. A higher mpg means less fuel per mile; a lower L/100km means less fuel per 100 km. The two are reciprocals, so they always move in opposite directions.
235.215 ÷ 6 = 39.2 mpg (US) — a very efficient petrol car. By European standards, 6 L/100km is a typical combined rating for a moderately efficient compact or mid-size car.