article MPG vs L/100km (2026) | 247QuickTools
⚖️ Comparison · Updated for 2026

MPG vs L/100km

Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.

Quick answer: MPG measures distance per unit fuel (higher = better). L/100km measures fuel per unit distance (lower = better). They are inverse, not linear. A car going from 30 to 40 mpg saves more fuel than going from 50 to 60 mpg — the L/100km figure shows this; MPG hides it.
Decision guide — when to use which
Use MPG when…

UK, US, Canada (alongside L/100km).

Use L/100km when…

All of continental Europe, Australia, New Zealand, official EU type-approval figures.

📊 Side-by-side comparison
Aspect MPG L/100km
Higher number is Better Worse
UK 40 mpg 40 UK mpg 7.06 L/100km
UK 60 mpg 60 UK mpg 4.71 L/100km
Why L/100km is better Quick comparison difficult Linear — easy to compare improvement
Used on car spec sheets UK, US All EU, Australia, NZ

Frequently asked

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Why is L/100km better than MPG?

L/100km is linear with fuel cost. Going from 8 L/100km to 6 L/100km saves the same fuel per km as going from 6 to 4. With MPG, the equivalent jumps (e.g. 30 to 40 mpg saves more than 50 to 60 mpg) — the relationship is not intuitive.

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Is MPG dying out?

In the EU, official figures are mandated in L/100km. The UK kept MPG by tradition. Even hybrid and EV efficiency in Europe is now sometimes given in kWh/100km, following the same 'usage per 100km' logic.

Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.

Frequently asked questions

Why is L/100km better than MPG?

L/100km is linear with fuel cost. Going from 8 L/100km to 6 L/100km saves the same fuel per km as going from 6 to 4. With MPG, the equivalent jumps (e.g. 30 to 40 mpg saves more than 50 to 60 mpg) — the relationship is not intuitive.

Is MPG dying out?

In the EU, official figures are mandated in L/100km. The UK kept MPG by tradition. Even hybrid and EV efficiency in Europe is now sometimes given in kWh/100km, following the same 'usage per 100km' logic.