MPG to L/100 km Converter

Fuel economy is measured in two distinct ways: distance per unit of fuel (such as miles per gallon) or fuel consumed per unit of distance (such as liters per 100 kilometers). Because the US gallon and the Imperial (UK) gallon are different sizes—where 1 UK gallon equals approximately 1.201 US gallons—conversions require specific scaling factors. To convert US MPG to Liters per 100 km, the standard formula is L/100 km = 235.215 / US MPG. For UK MPG, the formula uses 282.481 / UK MPG. When shifting to metric distance per volume, kilometers per liter (km/L) is simply the reciprocal of L/100 km multiplied by 100.

Let us convert a fuel efficiency of 30 US MPG into Liters per 100 km and kilometers per liter. First, apply the US conversion formula: divide 235.215 by 30 US MPG. This yields approximately 7.84 L/100 km, meaning the vehicle consumes 7.84 liters of fuel for every 100 kilometers traveled. To find the metric distance efficiency in km/L, divide the US MPG by 2.352 (or take the reciprocal of the L/100 km value), which gives roughly 12.75 km/L. This step-by-step logic allows you to accurately assess fuel burn regardless of the regional unit displayed on your dashboard.

When tracking your fuel economy, always use the fill-up method rather than relying solely on your dashboard computer for maximum accuracy. Note that switching between US and UK gallons is a common pitfall; a car rated at 40 UK MPG is significantly more efficient than one rated at 40 US MPG. Finally, remember that lower L/100 km numbers indicate better efficiency, whereas higher MPG and km/L numbers represent better efficiency.