Fuel Economy Converter

Compare fuel efficiency across US and metric measures.

How the Math Works

The Fuel Economy Converter uses liters per 100 kilometers (L/100km) as the universal conversion base. To convert MPG to L/100km, the formula is: L/100km = (235.215 / MPG). For km/L to L/100km: L/100km = 100 / km/L. Once you have the L/100km value, you can reverse the process: MPG = 235.215 / L/100km and km/L = 100 / L/100km. The constant 235.215 comes from converting miles per gallon to liters per 100 kilometers using standard conversion factors (1 mile = 1.60934 km, 1 US gallon = 3.78541 liters).

Practical Applications

To use this calculator, simply enter your vehicle's fuel economy in any unit—MPG, L/100km, or km/L—and instantly get equivalent values in the other two units. For example, if your car gets 25 MPG, the calculator shows approximately 9.4 L/100km and 10.6 km/L. This is especially useful when comparing fuel efficiency specifications for vehicles sold in different countries or when filling your tank and needing to calculate costs using local fuel pricing.

Day-to-Day Use

Understanding these conversions helps you make informed decisions about vehicle purchases, track your actual fuel usage, and budget for fuel expenses while traveling abroad. When shopping for a car, you can compare American MPG ratings with European L/100km ratings to find the most efficient option. While driving, you can convert your odometer readings to estimate fuel costs for road trips or verify if your vehicle is achieving its rated fuel economy.

Worked example

30 MPG → 7.84 L/100 km.

FAQ