Distance per Fuel Unit
MPG, km/L and mi/L measure how far a vehicle travels using one gallon or litre of fuel. A higher number indicates better fuel efficiency.
Understanding vehicle efficiency
What Is Fuel Economy?
Fuel economy describes how efficiently a vehicle uses fuel to travel a particular distance. Different countries use different measurement systems.
Fuel per Distance
L/100km and L/100mi measure how much fuel is needed to travel a fixed distance. A lower number indicates better fuel efficiency.
Simple conversion
How to Use the Fuel Economy Converter
The tool recalculates automatically whenever the value or selected unit changes.
Enter the fuel economy
Type the vehicle efficiency or fuel consumption value you want to convert.
Select the original unit
Choose US MPG, UK MPG, km/L, mi/L, L/100km or L/100mi.
Choose the output unit
Select the required destination measurement and view the converted result instantly.
Conversion formulas
Fuel Economy Conversion Formulas
Fuel economy conversions often use reciprocal formulas because efficiency and consumption move in opposite directions.
US MPG to L/100km
L/100km = 235.214583 ÷ US MPG
Example: 30 US MPG equals approximately 7.84049 L/100km.
UK MPG to L/100km
L/100km = 282.480936 ÷ UK MPG
Example: 40 UK MPG equals approximately 7.06202 L/100km.
km/L to L/100km
L/100km = 100 ÷ km/L
Example: 20 km/L equals exactly 5 L/100km.
L/100km to US MPG
US MPG = 235.214583 ÷ L/100km
Example: 8 L/100km equals approximately 29.4018 US MPG.
Common values
Common US MPG Conversion Table
These values show the relationship between US MPG, Imperial MPG, km/L and L/100km.
| US MPG | UK MPG | km/L | L/100km |
|---|---|---|---|
| 10 | 12.0095 | 4.25144 | 23.5215 |
| 20 | 24.0190 | 8.50288 | 11.7607 |
| 30 | 36.0285 | 12.7543 | 7.84049 |
| 40 | 48.0380 | 17.0058 | 5.88036 |
| 50 | 60.0475 | 21.2572 | 4.70429 |
| 60 | 72.0570 | 25.5086 | 3.92024 |
Important distinction
US MPG vs. Imperial MPG
US and Imperial gallons have different sizes, so their MPG values are not directly interchangeable.
US MPG
US MPG uses the US liquid gallon. One US gallon is approximately 3.78541 litres.
Imperial MPG
UK MPG uses the larger Imperial gallon. One Imperial gallon is approximately 4.54609 litres, so its numerical MPG value is higher for the same vehicle efficiency.
Helpful answers
Frequently Asked Questions
Divide 235.214583 by the US MPG value. For example, 30 US MPG equals approximately 7.84 L/100km.
US MPG uses the smaller US liquid gallon, while UK MPG uses the larger Imperial gallon. The same vehicle therefore has a higher UK MPG number.
Yes. Higher MPG means the vehicle travels farther using one gallon of fuel.
Yes. A lower L/100km value means the vehicle consumes less fuel over the same distance.
Divide 100 by the km/L value. For example, 20 km/L equals 5 L/100km.
Real fuel economy can change because of driving speed, traffic, road conditions, tyre pressure, vehicle load, weather, maintenance and driving behaviour.
No. It is an estimate based on the entered fuel economy and distance. Actual consumption may differ under real driving conditions.
Driving note:
Conversion results are mathematically equivalent values.
Actual vehicle fuel consumption may vary because of traffic,
speed, weather, maintenance, load and driving conditions.