Convert Gallons to Fluid Ounces

Convert Gallons (gal) to Fluid Ounces (fl oz) instantly and accurately.

Conversion Formula

fl oz = gal × 128

About Gallons

A US gallon (gal) = 4 quarts = 128 fl oz ≈ 3.785 L. Gasoline, milk, water, paint, and pesticides are sold by the gallon in the US. About 20% smaller than the UK imperial gallon (4.546 L) - a critical difference when comparing fuel economy across the Atlantic. 1 US gal = 3.785 L = 4 qt = 128 fl oz.

About Fluid Ounces

A fluid ounce (fl oz) is a US customary volume unit equal to 1/8 of a cup or 1/128 of a gallon - approximately 29.574 mL. Despite sharing a name with the weight unit 'ounce', fluid ounces measure volume, not mass. In the US, beverages are universally labeled in fluid ounces: a standard can of soda is 12 fl oz, a standard wine pour is 5 fl oz, and a shot of spirits is 1.5 fl oz. Note that the UK imperial fluid ounce (28.413 mL) differs slightly from the US fluid ounce (29.574 mL) - a common source of confusion in international recipes and product comparisons.

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