MPG (UK) to MPG (US) Converter
Enter a value below to convert UK miles per gallon to US miles per gallon. The two units use different gallons, so you multiply: mpg (US) = mpg (UK) × 0.83267418 - for example 40 mpg (UK) is 33.31 mpg (US). For the opposite direction, use our mpg (US) to mpg (UK) converter.
40 mpg (UK) = 33.31 mpg (US). Convert UK miles per gallon to US miles per gallon. Need the reverse? See mpg (US) to mpg (UK).
UK miles per gallon
- Definition
- UK miles per gallon (symbol: mpg (UK)) is a measure of fuel economy: the distance in miles a vehicle travels on one Imperial gallon of fuel (4.546 liters). A higher number means a more efficient car. Because the Imperial gallon is larger than the US gallon, the same car reads higher in UK MPG.
- History / origin
- It is built from the Imperial gallon, fixed at 4.546 liters in 1824, and the statute mile. Britain quoted fuel economy in miles per gallon for decades, and the figure outlived the switch to litres at the pump because drivers still think in MPG.
- Current use
- UK MPG is the everyday fuel-economy unit in the United Kingdom, used in car reviews, manufacturer brochures and trip-computer displays even though fuel itself is now sold in litres.
US miles per gallon
- Definition
- US miles per gallon (symbol: mpg (US)) is a measure of fuel economy: the distance in miles a vehicle travels on one US gallon of fuel (3.785 liters). A higher number means a more efficient car. Because the US gallon is smaller than the Imperial gallon, US MPG figures are always lower for the same vehicle.
- History / origin
- It is built from the US customary gallon, defined as 3.785 liters, and the statute mile. The US gallon is about five-sixths the size of the UK Imperial gallon, which is exactly why a UK MPG figure converts to a smaller US MPG figure.
- Current use
- US MPG is the standard fuel-economy unit in the United States, where EPA city and highway ratings appear on every new-car window sticker and in fuel-cost comparisons.
UK MPG to US MPG conversion table
| UK miles per gallon [mpg (UK)] | US miles per gallon [mpg (US)] |
|---|---|
| 20 mpg (UK) | 16.6534836926 mpg (US) |
| 25 mpg (UK) | 20.8168546157 mpg (US) |
| 30 mpg (UK) | 24.9802255389 mpg (US) |
| 35 mpg (UK) | 29.143596462 mpg (US) |
| 40 mpg (UK) | 33.3069673852 mpg (US) |
| 45 mpg (UK) | 37.4703383083 mpg (US) |
| 50 mpg (UK) | 41.6337092314 mpg (US) |
| 55 mpg (UK) | 45.7970801546 mpg (US) |
| 60 mpg (UK) | 49.9604510777 mpg (US) |
| 70 mpg (UK) | 58.287192924 mpg (US) |
Popular UK MPG to US MPG conversions
Everyday fuel-economy figures, rounded to two decimals - the kind of numbers you meet on real car specifications.
| UK miles per gallon [mpg (UK)] | US miles per gallon [mpg (US)] |
|---|---|
| 25 mpg (UK) | 20.82 mpg (US) |
| 30 mpg (UK) | 24.98 mpg (US) |
| 35 mpg (UK) | 29.14 mpg (US) |
| 40 mpg (UK) | 33.31 mpg (US) |
| 45 mpg (UK) | 37.47 mpg (US) |
| 50 mpg (UK) | 41.63 mpg (US) |
| 55 mpg (UK) | 45.80 mpg (US) |
| 60 mpg (UK) | 49.96 mpg (US) |
| 70 mpg (UK) | 58.29 mpg (US) |
| 80 mpg (UK) | 66.61 mpg (US) |
How to convert MPG (UK) to MPG (US)
To convert UK MPG to US MPG, multiply the mpg (UK) value by 0.83267418. The two units measure the same fuel economy but with different gallons, so the conversion is a single multiplication. For example, 40 mpg (UK) = 40 × 0.83267418 = 33.31 mpg (US).
The factor 0.83267418 is simply the ratio of the US gallon (3.785 liters) to the UK Imperial gallon (4.546 liters). The reverse direction multiplies by 1.20094993:
mpg (US) = mpg (UK) × 0.83267418
mpg (UK) = mpg (US) × 1.20094993
Example. A car rated at 50 mpg (UK) does 50 × 0.83267418 = 41.63 mpg (US), while a frugal 60 mpg (UK) does 60 × 0.83267418 = 49.96 mpg (US).
When you need to convert MPG (UK) to MPG (US)
Drivers and buyers move between UK and US miles per gallon whenever a British fuel-economy figure has to make sense to an American audience. Common cases:
- Reading a UK car review's mpg (UK) rating as a familiar US MPG number.
- Comparing a UK-market model's spec sheet against US EPA MPG ratings.
- Working out the real US MPG of a car whose brochure quotes Imperial gallons.
- Translating a UK manufacturer's MPG claim so it compares fairly against US figures.
- Avoiding the trap of assuming a UK MPG number means the same in the US.
Frequently asked questions
How do I convert UK miles per gallon to US miles per gallon?
Multiply the mpg (UK) value by 0.83267418. For example, 40 mpg (UK) equals 40 × 0.83267418 = 33.31 mpg (US). US MPG figures are always lower because the US gallon is smaller than the Imperial gallon.
What is 40 mpg (UK) in mpg (US)?
40 mpg (UK) is 33.31 mpg (US), found by multiplying 40 by 0.83267418. The same car appears thirstier in US MPG only because the US gallon holds less fuel.
What is the mpg (UK) to mpg (US) formula?
The formula is mpg (US) = mpg (UK) × 0.83267418. The factor is just the ratio of the US gallon (3.785 liters) to the UK Imperial gallon (4.546 liters), so it is a simple linear conversion.
Is this the US or UK gallon?
Both. The source figure uses the UK Imperial gallon of 4.546 liters and the result uses the US gallon of 3.785 liters. Because the US gallon is smaller, the same fuel economy is a lower number in US MPG.
What is a good mpg (UK) figure in mpg (US)?
Around 50 to 60 mpg (UK), or about 42 to 50 mpg (US), is efficient for a modern petrol car. 40 mpg (UK) is 33.31 mpg (US), while under 30 mpg (UK), below 25 mpg (US), is thirsty.
How do I convert mpg (US) back to mpg (UK)?
Multiply the mpg (US) value by 1.20094993, or use our mpg (US) to mpg (UK) converter. For example, 30 mpg (US) is 30 × 1.20094993 = 36.03 mpg (UK).
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