Gas Mileage Calculator · Practical guide
MPG to L/100km Conversion
Divide 235.21 by your MPG to get L/100km — lower is better, the opposite of MPG.
At a glance
The Conversion Formula
To convert US miles per gallon to liters per 100 kilometers, divide 235.21 by the MPG figure: L/100km = 235.21 ÷ MPG. So 30 MPG converts to 235.21 ÷ 30 = 7.84 L/100km. The calculator above shows both units side by side every time you enter distance and fuel.
Interactive tool
Gas Mileage Calculator
Enter your own values, then compare the result with the examples below.
Mileage Results
Why the Two Numbers Move in Opposite Directions
MPG measures how far you go on a fixed amount of fuel, so higher is better. L/100km measures how much fuel you burn over a fixed distance, so lower is better. They are inverse views of the same efficiency, which is why a jump from 15 to 20 MPG (15.7 to 11.8 L/100km) saves far more fuel than a jump from 40 to 45 MPG.
MPG to L/100km Conversion Table
| MPG (US) | L/100km |
|---|---|
| 15 | 15.68 |
| 20 | 11.76 |
| 25 | 9.41 |
| 30 | 7.84 |
| 35 | 6.72 |
| 40 | 5.88 |
| 50 | 4.70 |
A Note on US vs UK Gallons
This conversion uses the US gallon (3.785 liters). The UK imperial gallon is about 20% larger, so UK MPG figures convert differently — divide 282.48 by UK MPG instead. When comparing international specs, check which gallon the number is based on.
Frequently Asked Questions
What is 25 MPG in L/100km?
25 US MPG equals about 9.41 L/100km, using the formula 235.21 divided by 25.
Is a lower L/100km better?
Yes. L/100km measures fuel consumed over a set distance, so smaller numbers mean better fuel efficiency — the opposite of MPG.
Why is the conversion factor 235.21?
It comes from the unit relationships: 100 kilometers divided by the miles per US gallon conversion (1.609 km per mile and 3.785 liters per gallon) yields about 235.21.
How do I convert L/100km back to MPG?
Use the same factor in reverse: MPG = 235.21 divided by L/100km. For example, 8 L/100km equals about 29.4 MPG.