⚖️ Comparison · Updated for 2026
MPG (UK) vs MPG (US)
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: 1 UK MPG ≈ 0.833 US MPG. UK MPG figures are about 20% higher than US MPG for the same engine — purely because the UK gallon (4.546 L) is 20% bigger than the US gallon (3.785 L). A UK car claiming '60 MPG' is the same as 'about 50 MPG' on US figures.
Decision guide — when to use which
Use MPG (UK) when…
UK car magazines, UK marketing, older UK consumer references.
Use MPG (US) when…
US car magazines, EPA fuel economy ratings, North American marketing.
📊 Side-by-side comparison
| Aspect | MPG (UK) | MPG (US) |
|---|---|---|
| Gallon size | 4.546 L (UK Imperial) | 3.785 L (US wine gallon) |
| Conversion | ×0.833 → US MPG | ×1.201 → UK MPG |
| UK 60 MPG | 60 UK MPG | 50 US MPG |
| UK 40 MPG | 40 UK MPG | 33.3 US MPG |
| Metric equivalent | L/100km (Europe) | L/100km (Europe) |
Frequently asked
?
Why are UK MPG figures higher than US MPG for the same car?
Pure unit difference. The UK gallon is 20% bigger than the US gallon, so the same car achieves 20% more 'miles per gallon' on the UK measure. The actual fuel economy is identical.
?
What's the metric way of saying this?
L/100km. Lower numbers are better (less fuel for the same distance). 50 mpg UK ≈ 33.3 mpg US ≈ 5.65 L/100km.
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 All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications).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.