MPG (UK)
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Equivalent fuel economy
Accurate fuel economy conversion between American and British miles per gallon
Convert MPG (US) to MPG (UK) instantly with precise calculations. Includes bidirectional conversion and detailed fuel economy breakdowns for 2026.
Professional fuel economy conversion for drivers, engineers, and vehicle buyers
Convert miles per gallon (US) to miles per gallon (UK) with precision. The tool uses the exact ratio between the US gallon (3.78541 litres) and the imperial gallon (4.54609 litres), so your fuel economy figures are consistent across both systems.
Switch seamlessly between MPG (US) to MPG (UK) and MPG (UK) to MPG (US) conversion modes. Get instant results alongside equivalent values in litres per 100km and kilometres per litre for easier comparison between US and European vehicle data.
Ideal for car importers, international buyers, fleet managers, and drivers reading car reviews from different countries. Instantly translate fuel economy figures from American specs to British/European equivalents in 2026.
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Both MPG (US) and MPG (UK) measure how far a vehicle can travel on one gallon of fuel, but they use different gallon sizes. The US gallon is defined as 3.78541 litres, while the British imperial gallon is 4.54609 litres. Because the UK gallon is larger, the same vehicle will show a higher MPG number on the UK scale than on the US scale.
This difference is crucial when comparing car reviews, brochures, or online listings from different countries. A car that achieves 30 MPG (US) will achieve over 36 MPG (UK) for the same real-world fuel usage. To keep your comparisons consistent, always convert US figures to UK figures (or vice versa) before making decisions about fuel economy and running costs.
The factor 1.20095 comes from dividing the imperial gallon size by the US gallon size: 4.54609 ÷ 3.78541.
Suppose your car achieves 30 MPG (US) according to an American review. To convert this to MPG (UK):
MPG (UK) = 30 × 1.20095 = 36.03 MPG (UK)
This means a UK driver would describe the same car as achieving about 36 MPG, even though the actual fuel consumption is identical.
For any given car, MPG (UK) will always be higher than MPG (US) because the imperial gallon is larger.
Use this reference table to quickly look up typical MPG (US) values and their corresponding MPG (UK), litres per 100km, and km per litre. This is especially useful when comparing American and European car specifications.
| MPG (US) | MPG (UK) | L/100km | km per Litre | Efficiency Rating |
|---|---|---|---|---|
| 15 MPG | 18.0 MPG | 15.68 L/100km | 6.38 km/L | Poor |
| 20 MPG | 24.0 MPG | 11.76 L/100km | 8.50 km/L | Below Average |
| 25 MPG | 30.0 MPG | 9.41 L/100km | 10.63 km/L | Average |
| 30 MPG | 36.0 MPG | 7.84 L/100km | 12.75 km/L | Good |
| 35 MPG | 42.0 MPG | 6.72 L/100km | 14.89 km/L | Good |
| 40 MPG | 48.0 MPG | 5.88 L/100km | 16.99 km/L | Very Good |
| 45 MPG | 54.0 MPG | 5.23 L/100km | 19.09 km/L | Very Good |
| 50 MPG | 60.0 MPG | 4.70 L/100km | 21.25 km/L | Excellent |
| 55 MPG | 66.0 MPG | 4.29 L/100km | 23.32 km/L | Excellent |
| 60 MPG | 72.0 MPG | 3.92 L/100km | 25.47 km/L | Exceptional |
| 70 MPG | 84.1 MPG | 3.36 L/100km | 29.75 km/L | Exceptional |
| 80 MPG | 96.1 MPG | 2.94 L/100km | 33.97 km/L | Exceptional |
The US gallon contains 3.78541 litres, while the imperial gallon used in the UK contains 4.54609 litres. Because the UK gallon is around 20% larger, a car rated at 30 MPG (US) will show about 36 MPG (UK) for the same real-world fuel usage.
When reading car reviews from American and British sources, fuel economy figures can look very different. Converting MPG (US) to MPG (UK) makes it easier to compare models fairly and estimate fuel costs accurately for your country in 2026.
Most European markets use litres per 100km instead of miles per gallon. For example, 30 MPG (US) roughly equals 7.8 L/100km. Converting to L/100km is helpful when comparing American cars with European models and fuel consumption standards.
You do not need complex calculations for everyday use. Multiplying MPG (US) by 1.20 gives a good estimate of MPG (UK), and multiplying MPG (UK) by 0.83 gives a good estimate of MPG (US). These rounded factors are accurate enough for most practical decisions.
Official MPG figures in both the US and UK come from controlled test cycles. Real-world consumption is usually 10–25% worse, depending on driving style, speed, climate, and load. When converting MPG (US) to MPG (UK), remember that both numbers are still optimistic compared to real driving conditions.
Learn how MPG (US), MPG (UK), L/100km, and km per litre relate to each other, and how to make fair comparisons between cars from different markets in 2026.
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