MPG vs L/100km: Understanding Fuel Economy Worldwide
Learn the differences between fuel economy measurements and how to convert between MPG and L/100km.
Fuel economy is measured differently around the world, which can make comparing vehicles confusing. The United States uses miles per gallon (MPG), while most other countries use liters per 100 kilometers (L/100km) or kilometers per liter (km/L).
Understanding the Different Units
Miles Per Gallon (MPG)
Used in the US and UK (note: US and Imperial gallons are different sizes). Higher MPG means better fuel economy. A car getting 30 MPG travels 30 miles on one gallon of fuel.
Liters per 100 Kilometers (L/100km)
Used in Europe, Australia, and many other countries. Lower L/100km means better fuel economy. A car rated at 6 L/100km uses 6 liters of fuel to travel 100 kilometers.
Kilometers per Liter (km/L)
Used in some Asian countries including Japan and India. Higher km/L means better fuel economy.
The Inverse Relationship
The trickiest part of fuel economy conversion is that MPG and L/100km have an inverse relationship. When MPG goes up, L/100km goes down. The formula is:
- L/100km = 235.215 ÷ MPG (US)
- MPG (US) = 235.215 ÷ L/100km
Quick Reference Table
| MPG (US) | L/100km | km/L |
|---|---|---|
| 20 | 11.76 | 8.50 |
| 25 | 9.41 | 10.63 |
| 30 | 7.84 | 12.75 |
| 35 | 6.72 | 14.88 |
| 40 | 5.88 | 17.00 |
| 50 | 4.70 | 21.25 |
US vs Imperial Gallons
Be careful when comparing US and UK fuel economy. An Imperial gallon is larger than a US gallon (4.546L vs 3.785L), so the same car will have a higher MPG number in the UK than in the US.
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