Fuel Economy Converter Formula

Understand the math behind the fuel economy converter. Each variable explained with a worked example.

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Formulas Used

Liters per 100 km

l_per_100km = mpg > 0 ? 235.215 / mpg : 0

Kilometers per Liter

km_per_liter = mpg * 0.425144

Miles per Liter

miles_per_liter = mpg * 0.264172

Variables

VariableDescriptionDefault
mpgMiles per Gallon (MPG)(mpg)30

How It Works

Fuel Economy Conversion

L/100km = 235.215 / MPG

km/L = MPG × 0.4251

MPG is used in the US and UK. L/100km is the standard in most other countries. Lower L/100km = better fuel economy.

Worked Example

A car with 30 MPG fuel economy.

mpg = 30
  1. 01L/100km = 235.215 / 30 = 7.8 L/100km
  2. 02km/L = 30 × 0.4251 = 12.8 km/L

Ready to run the numbers?

Open Fuel Economy Converter