Fuel Economy Converter

Convert fuel consumption between L/100 km, km/L and mpg (US & UK) — instantly.

Result

Result

29.40

How it works

Lower L/100 km = better; higher mpg / km/L = better

Fuel economy is measured two opposite ways. Litres per 100 km counts fuel for a fixed distance, so lower is better; miles per gallon counts distance for a fixed fuel, so higher is better. This converter moves between them and km/L. Because they are reciprocals, the conversion is not a simple scale factor: mpg = 235.2 ÷ (L/100 km) for US gallons. That reciprocal relationship has a counterintuitive consequence — equal steps in mpg are not equal savings. Going from 10 to 15 mpg saves far more fuel over the same distance than going from 30 to 35, even though both are five miles per gallon. That is why L/100 km is the more honest metric for comparing running costs: it is directly proportional to what you actually spend at the pump.

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Frequently asked questions

How do I convert L/100 km to mpg?

mpg (US) = 235.21 ÷ (L/100 km). Example: 8 L/100 km ≈ 29.4 mpg.

Is a lower L/100 km better?

Yes — the car uses less fuel. For mpg and km/L, higher is better.

Why is the conversion not linear?

Because the two units are inverses of each other, so the relation is a reciprocal, not a multiplication. It also means improvements at low mpg matter far more than the same numerical gain at high mpg — the fuel saved is what counts, not the number of miles per gallon.

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