Fuel Economy Converter
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Note: mpg and L/100km are inversely related — a higher mpg means a lower L/100km.
Fuel economy can be expressed as distance per fuel (mpg, km/L) or fuel per distance (L/100km). These are inverses: a car that does 30 mpg (US) uses about 7.84 L/100km.
The conversion is non-linear (reciprocal), so it can't be done with a simple multiply. This converter applies the correct reciprocal relationship (1 mpg US = 235.215/100 L/100km⁻¹) and handles km/L as well.
Common applications
Comparing a US mpg rating to a European L/100km; estimating fuel cost for a trip; converting a car's km/L to mpg.
Frequently asked questions
Because they're inverses. mpg = distance/fuel; L/100km = fuel/distance. Converting requires a reciprocal.
L/100km = 235.215 / mpg. So 30 mpg ≈ 7.84 L/100km.
US mpg (231 in³/gal). Imperial mpg (UK) uses a larger gallon and differs by ~20%.