Marks Calc
4 units

Fuel Economy Converter

Fuel economy is non-linear: mpg and L/100km are inversely proportional. A higher mpg means lower L/100km.

Common fuel economy conversions

FromEquivalent
1 L/100km235.2146 mpg (US) · 282.4809 mpg (UK) · 100 km/L
5 L/100km47.0429 mpg (US) · 56.4962 mpg (UK) · 20 km/L
10 L/100km23.5215 mpg (US) · 28.2481 mpg (UK) · 10 km/L
100 L/100km2.3521 mpg (US) · 2.8248 mpg (UK) · 1 km/L
1000 L/100km0.2352 mpg (US) · 0.2825 mpg (UK) · 0.1 km/L

How the conversion works

Inverse relationship: `L/100km = 235.21 / mpg (US)` and `L/100km = 282.48 / mpg (UK)`. `km/L = 100 / L/100km`.

When you'll use this converter

  • Comparing car efficiency across regions (US vs Europe)
  • Trip cost estimation
  • Vehicle reviews and spec comparisons

Frequently asked

Why is mpg not just a linear conversion?

Because mpg is distance per fuel, while L/100km is fuel per distance — they are reciprocals of each other after unit conversion.

Is 30 mpg good?

30 mpg (US) ≈ 7.84 L/100km — middling for a modern petrol car. Hybrids commonly hit 40–55 mpg (4.3–5.9 L/100km).