MPG vs L/100km
MPG measures distance per unit of fuel — higher is better. L/100km measures fuel used per distance — lower is better.
L/100km = 235.215 ÷ MPG (US)
So 30 US MPG ≈ 7.8 L/100km.
UK gallons are larger than US gallons (4.546 L vs 3.785 L), so UK MPG figures look higher for the same real efficiency.
Frequently asked questions
How do I convert MPG to L/100km?
Divide 235.215 by the US MPG. 40 MPG ≈ 5.9 L/100km.
Is higher or lower better?
Higher MPG is better; lower L/100km is better.
Are US and UK MPG the same?
No — a UK gallon is ~20% larger, so UK MPG figures look higher for the same efficiency.