What is the exact conversion factor from MPG to km/L?

1 US MPG = 0.425144 km/L. This comes from 1 mile = 1.60934 km and 1 US gallon = 3.78541 L, giving 1.60934 / 3.78541 ≈ 0.425144.

Is this US gallons or UK (Imperial) gallons?

This tool uses US gallons (3.78541 L). UK Imperial MPG uses a larger gallon (4.54609 L), so 1 UK MPG ≈ 0.354006 km/L — a different conversion. Always check which standard a vehicle spec uses.

How do I convert km/L back to US MPG?

Divide the km/L value by 0.425144. For example, 15 km/L ÷ 0.425144 ≈ 35.3 MPG. You can also use the Swap button in this tool to flip the direction.

What is a good fuel economy in km/L?

A typical efficient passenger car gets 15–20 km/L (35–47 MPG US). Hybrids often exceed 20 km/L. Heavy trucks and SUVs usually fall below 10 km/L (under 24 MPG).

Why do some countries use L/100km instead of km/L?

L/100km is common in Europe, Australia, and Canada. It expresses consumption (lower = better), while km/L expresses efficiency (higher = better). To convert km/L to L/100km, compute 100 ÷ km/L.

MPG (US) to km/L Converter

Name: MPG (US) to km/L Converter
Availability: InStock
Author: Nham Vu

Enter a fuel economy value in US MPG and instantly get the equivalent in km/L (1 MPG US = 0.425144 km/L).

Fuel Economy Converter

Miles Per Gallon (US MPG)

MPG

Kilometers Per Liter (km/L)

km/L

Result

Enter a value to see the result

1 US MPG = 0.425144 km/L | 1 km/L ≈ 2.35214 MPG

Common Conversions

MPG (US)	km/L	Typical Vehicle

Summary

Enter a fuel economy value in US MPG and instantly get the equivalent in km/L (1 MPG US = 0.425144 km/L).

How it works

Enter your fuel economy value in the MPG or km/L field.
The converter applies the exact factor: 1 MPG (US) = 0.425144 km/L.
The equivalent value appears instantly in the other field.
Use the Swap button to reverse the conversion direction.
Copy the result with one click for use elsewhere.

Use cases

Convert a car's US MPG rating to km/L for international comparison.
Check if an imported vehicle meets local fuel economy expectations.
Compare fuel efficiency between US and metric spec sheets.
Convert rental car economy ratings when traveling abroad.
Quickly sanity-check fuel costs before a road trip.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu