Convert UK Gallon to Fluid Ounce (gal (UK) → fl oz)

Converting UK gallons to fluid ounces 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 153.72159

   The conversion factor from gal (UK) to fl oz is 153.72159. Multiply your value by this number.
3. 3
   Read the result in fluid ounces

   The result is your value in fluid ounces (fl oz).

Multiply the value in UK gallons by 153.72159. For the reverse direction, multiply by 0.006505.

• ✓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 Fluid Ounce?

The US fluid ounce equals exactly 29.5735295625 milliliters and is the standard small-volume unit for beverages, cocktails, personal-care products, and cooking in the United States. It is distinct from the (weight) ounce: 1 fluid ounce of water weighs about 1 ounce by weight at room temperature, but other liquids may weigh more or less. Soft-drink cans (12 fl oz), beer bottles (12 fl oz), shampoo bottles, and skin-cream tubs all label volume in fluid ounces. The US fluid ounce is slightly different from the UK imperial fluid ounce (28.4131 mL — about 4% smaller), reflecting the different gallon definitions. The US fl oz relates to the gallon (128 fl oz = 1 gal), the cup (8 fl oz = 1 cup), the tablespoon (2 tbsp = 1 fl oz), and the milliliter (1 fl oz ≈ 29.57 mL). Cocktail recipes universally use fluid ounces.

• US beverage and soda can sizes (12 fl oz)
• Cosmetic and personal-care product volumes
• US fluid recipes and cocktail measures