Cups to Gallons Converter

How to convert cups to gallons

1 cup = 0.0625 gallons. To convert cups to gallons, divide by 16 (or multiply by 0.0625). A US customary cup is 8 US fluid ounces, about 236.6 ml (nutrition labels use a rounded 240 ml). A US liquid gallon is 231 cubic inches, exactly 3.785411784 L.

Worked examples

• 8 cups = 0.5 gal (8 ÷ 16)
• 16 cups = 1 gal (16 ÷ 16)
• 64 cups = 4 gal (64 ÷ 16)

Where this conversion comes up

Cups are used for US recipes and nutrition labels; gallons for gasoline, milk, paint and fish tanks in the US. A US gallon is 16 cups, so 8 cups is half a gallon and 64 cups is 4 gallons. The '8 cups of water a day' guideline is half a gallon.

Quick estimate

Divide by 16.

Common mistakes

• Multiplying instead of dividing. A gallon is larger than a cup, so the number of gallons must come out smaller: 8 cups = 0.5 gal.
• Mixing fluid ounces with weight ounces. A fluid ounce is a volume (29.57 ml); an ounce on a kitchen scale is a weight (28.35 g). A cup of flour is 8 fl oz by volume but only about 4.25 oz by weight.
• Using the imperial (UK) unit. This page uses US measures. An imperial gallon is 4.546 L (20% more than a US gallon), an imperial pint 568 ml and an imperial fluid ounce 28.41 ml.
• Rounding too early. Keep the full factor until the last step; rounding 0.0625 to 0.06 first puts large values noticeably off.

Going the other way? Use the gallons to cups converter. Related volume converters: ml to oz, oz to ml, liters to gallons, gallons to liters, liters to quarts, quarts to liters.