Convert UK Gallon to US Gallon (gal (UK) → gal (US))

Converting UK gallons to US gallons is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in UK gallons

   Start with the number of UK gallons (gal (UK)) you want to convert.
2. 2
   Multiply by 1.20095

   The conversion factor from gal (UK) to gal (US) is 1.20095. Multiply your value by this number.
3. 3
   Read the result in US gallons

   The result is your value in US gallons (gal (US)).

Multiply the value in UK gallons by 1.20095. For the reverse direction, multiply by 0.832674.

• ✓1 UK gallon = 4.54609 L exactly = 160 UK fluid ounces.
• ✓1 UK gallon ≈ 1.201 US gallons.
• ✓UK mpg × 0.832 = US mpg (same car, different unit).

• ✗Comparing UK mpg with US mpg directly — UK figures are about 20% higher for the same car.
• ✗Using 4.5 L instead of 4.546 L for precise conversion.
• ✗Assuming modern UK car ads quote US gallons — they always use UK gallons.

What is the UK Gallon?

The UK imperial gallon equals exactly 4.54609 liters and is approximately 20% larger than the US gallon. Established by the British Weights and Measures Act of 1824 to standardize earlier ale and corn gallons, the imperial gallon was designed so that 10 pounds of pure water at 62°F occupied exactly 1 gallon. Although the United Kingdom has officially adopted the liter for fuel sales since 1995, the imperial gallon persists in everyday speech ('miles per gallon' for car fuel economy) and remains the standard unit in some Caribbean and Pacific Commonwealth countries. The imperial gallon relates to the US gallon (1 imp gal ≈ 1.201 US gal), the imperial quart (4 imp qt = 1 imp gal), the imperial pint (8 imp pt = 1 imp gal — the famous British pint of beer), and the liter (1 imp gal ≈ 4.546 L).

• UK fuel economy in miles per gallon (UK mpg)
• Older British industrial and brewing contexts
• Commonwealth countries that retain imperial measures

What is the US Gallon?

The US liquid gallon equals exactly 3.785411784 liters and is the standard volume unit for fuel, beverages, milk, and household liquids in the United States. Defined as 231 cubic inches, the US gallon descends from the English wine gallon of 1707, which Britain replaced with the larger imperial gallon in 1824 — a divergence that left the United States with a different gallon than the rest of the English-speaking world. American gas stations price gasoline by the gallon (typical fill-up: 12–15 gallons), milk is sold in half-gallons and gallons, and many beverages come in fluid-ounce subdivisions of the gallon. The US gallon relates to the liter (1 gal ≈ 3.785 L), the quart (4 qt = 1 gal), the pint (8 pt = 1 gal), the cup (16 cups = 1 gal), and the imperial gallon (1 imp gal ≈ 1.201 US gal — about 20% larger).

• US fuel pricing and consumption
• US paint, oil and cleaning-product packaging
• US beverage containers (1-gallon jugs of milk)