Fuel Efficiency Converter
Convert between all major fuel economy units instantly. Enter any value in MPG, litres per 100 km, km per litre, or miles per litre and get precise results for cars, motorcycles, and fleet vehicles.
Quick Reference Formulas
Fuel Efficiency Conversion Table
| MPG (US) | MPG (UK) | km/L | L/100km | mi/L |
|---|---|---|---|---|
| 10 | 12.01 | 4.251 | 23.52 | 2.642 |
| 15 | 18.01 | 6.376 | 15.68 | 3.963 |
| 20 | 24.02 | 8.502 | 11.76 | 5.284 |
| 25 | 30.02 | 10.63 | 9.408 | 6.604 |
| 30 | 36.03 | 12.75 | 7.840 | 7.925 |
| 35 | 42.03 | 14.88 | 6.720 | 9.246 |
| 40 | 48.04 | 17.00 | 5.880 | 10.57 |
| 45 | 54.04 | 19.13 | 5.227 | 11.89 |
| 50 | 60.05 | 21.25 | 4.704 | 13.21 |
| 60 | 72.06 | 25.50 | 3.920 | 15.85 |
About Fuel Efficiency Units
Fuel efficiency describes how far a vehicle travels per unit of fuel consumed. The United States and United Kingdom use miles per gallon (MPG), though their gallon sizes differ — the US gallon is 3.785 litres while the imperial (UK) gallon is 4.546 litres, making UK MPG figures about 20% higher for the same vehicle.
Europe and most of the world use litres per 100 kilometres (L/100km), where a lower number means better economy. Japan and India often use km per litre (km/L or kmpl), which is directly proportional to MPG. These units are mathematically related: km/L × 2.352 = MPG (US) and L/100km = 235.21 ÷ MPG (US).
Common Fuel Efficiency Conversions
Worked Examples
30 MPG (US) to L/100km
Use the inverse formula: L/100km = 235.21 ÷ MPG (US)
235.21 ÷ 30 = 7.84
8 L/100km to MPG (US)
MPG (US) = 235.21 ÷ L/100km
235.21 ÷ 8 = 29.4
15 km/L to L/100km
L/100km = 100 ÷ km/L
100 ÷ 15 = 6.67
40 MPG (US) to MPG (UK)
Multiply by the gallon ratio: 4.54609 ÷ 3.78541 = 1.2009
40 × 1.2009 = 48.04
When You Need Fuel Efficiency Conversions
Car Buying
Compare fuel economy across vehicles rated in different units — US MPG vs. European L/100km specs.
Road Trip Planning
Estimate total fuel cost for a journey by knowing your car\u2019s efficiency in local units.
Fleet Management
Track fuel consumption across international fleets where vehicles are rated in different standards.
Emissions Tracking
CO\u2082 emissions correlate directly with fuel use — convert to L/100km for standardised emissions calculations.
Driving Efficiency
Monitor real-world mpg vs. manufacturer\u2019s rated figure to evaluate driving habits and maintenance needs.
Insurance & Tax
Some insurance and road-tax schemes use fuel economy bands — ensure you\u2019re comparing in the right units.
Mental Math Tips
Divide 235 by any US MPG figure to quickly get the approximate litres per 100 km equivalent.
Multiply km/L by 2.35 for a fast MPG estimate — useful when reading Indian car spec sheets.
Multiply any US MPG value by 0.425 to get the rough km/L (kmpl) equivalent instantly.