Gallons to Ounces (gal to fl oz)

How to convert gallons to ounces

Multiply U.S. gallons by 128:

fluid ounces = gallons × 128

1.5 gal × 128 = 192 fl oz. The number comes from the U.S. system’s halving steps: a gallon is 4 quarts, a quart 2 pints, a pint 2 cups and a cup 8 fluid ounces — 4 × 2 × 2 × 8 = 128. To go the other way, divide fluid ounces by 128.

For milliliters, multiply the ounces by 29.57, or use ounces to mL; for liters, see gallons to liters.

Gallons to ounces chart

To convert a list, open Convert a list of values and paste the gallons one per line.

Bottles and glasses in a gallon

Container sizes are nominal: a bottle labeled 16.9 fl oz may be filled slightly under or over, so treat these counts as planning figures rather than exact pours. Planning drinks for a crowd: at 8 fl oz per serving, each gallon serves 16, so 5 gallons covers 80 servings.

Gallons, quarts, pints and cups

Because each U.S. measure is double the one below it, you can move between them without a calculator: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces. A recipe that calls for 3 quarts of stock needs 96 fl oz, which is three-quarters of a gallon.

UK gallons

A UK (imperial) gallon is 4.546 liters and holds 160 UK fluid ounces — but because the UK fluid ounce (28.41 mL) is smaller than the U.S. one (29.57 mL), that is 153.72 U.S. fluid ounces. Choose UK gallon above the field for imperial measures; the result shows both kinds of fluid ounce. For pounds of water, a U.S. gallon weighs about 8.34 lb — see kg to lbs for other weights.