How Many Cups in a Gallon? Full Conversion Chart

Quick Answer: 16 Cups in One US Gallon

One US liquid gallon contains exactly 16 cups. This comes from the US liquid measurement hierarchy: 2 cups = 1 pint, 2 pints = 1 quart, 4 quarts = 1 gallon. So: 2 × 2 × 4 = 16 cups per gallon.

US Liquid Measurement Hierarchy

Unit	Fluid Ounces	Cups	Milliliters
1 tablespoon	0.5 fl oz	1/16 cup	14.8 mL
1 cup	8 fl oz	1 cup	237 mL
1 pint	16 fl oz	2 cups	473 mL
1 quart	32 fl oz	4 cups	946 mL
½ gallon	64 fl oz	8 cups	1,893 mL
1 gallon	128 fl oz	16 cups	3,785 mL

Cups in a Gallon: Common Amounts

• ¼ gallon = 4 cups
• ½ gallon = 8 cups
• ¾ gallon = 12 cups
• 1 gallon = 16 cups
• 2 gallons = 32 cups

US Gallon vs. UK Imperial Gallon

The US gallon (3.785 liters) is smaller than the UK imperial gallon (4.546 liters). If you're following a British recipe that calls for a gallon, it uses about 20% more liquid. A UK gallon = approximately 18.18 US cups.

Practical Examples

Making a large batch of lemonade: Most lemonade recipes make 1 quart (4 cups). To make a full gallon for a party, multiply all ingredients by 4.

Filling a fish tank: A 10-gallon aquarium holds 160 cups or 1,280 fluid ounces of water.

Buying milk: A half-gallon milk carton = 8 cups = enough for about 8 bowls of cereal with 1 cup of milk each.

Memory Trick

A handy way to remember the US liquid hierarchy is the word "GQPC" — Gallon, Quart, Pint, Cup — where each step halves the previous: 1 gallon = 4 quarts = 8 pints = 16 cups.