# Free online fuel economy converter

> Fuel efficiency is measured differently around the world — MPG in the US and UK, L/100km in Europe, and km/L in Asia. This converter shows all five common units at once.

Convert fuel economy between MPG (US), MPG (UK), km/L, L/100km, and L/100mi instantly. See all equivalents in a single table. Useful for comparing cars across countries.

**Interactive version:** https://onlinecalculator.me/unit-converters/fuel-economy/
**Category:** Unit Converters

## How to use

1. Enter a fuel economy value.
2. Select the unit you are converting **from**.
3. Select the unit you want to convert **to**.
4. The result and a full conversion table appear instantly.
5. Click "Share with my numbers" to copy a URL with your inputs.

## Conversion formulas

All conversions use L/100km as the internal reference:

| From | To L/100km |
|------|-----------|
| MPG (US) | 235.215 ÷ mpg |
| MPG (UK) | 282.481 ÷ mpg_uk |
| km/L | 100 ÷ kml |
| L/100km | (no change) |
| L/100mi | value × 100 ÷ 160.934 |

## Worked example

**30 MPG (US)** converted:

- L/100km = 235.215 ÷ 30 = **7.84 L/100km**
- MPG (UK) = 282.481 ÷ 7.84 = **36.03 MPG UK**
- km/L = 100 ÷ 7.84 = **12.76 km/L**

## Notes

- Constants: 1 US gallon = 3.785411784 L; 1 UK gallon = 4.54609 L; 1 mile = 1.609344 km.
- Source: US EPA fuel economy methodology; Wikipedia "Fuel efficiency" (https://en.wikipedia.org/wiki/Fuel_efficiency).
- L/100km and L/100mi use an inverse relationship to distance — lower is more efficient.

## Frequently asked questions

### How do you convert MPG to L/100km?

Divide 235.21 by the MPG value. Example: 30 MPG = 235.21 ÷ 30 ≈ 7.84 L/100km.

### How do US MPG and UK MPG differ?

The UK gallon (imperial gallon) is larger than the US gallon — 4.546 L vs 3.785 L. So 1 UK MPG ≈ 1.2009 US MPG. A car rated 40 MPG UK is about 33 MPG US.

### Is a higher or lower L/100km better?

Lower is better for L/100km and L/100mi — they measure how much fuel you use per distance. Higher is better for MPG and km/L — they measure how far you go per unit of fuel.

### What is km/L?

Kilometers per liter (km/L) is used in Japan, India, and some other countries. It is mathematically equivalent to MPG but using metric units. 1 km/L ≈ 2.352 US MPG.

### What is the formula for L/100km to MPG?

MPG = 235.215 ÷ L/100km. Example: 8 L/100km = 235.215 ÷ 8 ≈ 29.4 MPG (US).

## Sources

- [Fuel economy in automobiles — MPG, L/100km and conversions](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles) — Wikipedia
- [How Vehicles Are Tested — official EPA/DOE fuel economy method](https://www.fueleconomy.gov/feg/how_tested.shtml) — U.S. DOE / EPA (FuelEconomy.gov)

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