How many cups in a gallon?

1 gallon = 16 cups

1/2 gallon = 8 cups · 1/4 gallon = 4 cups · 128 fl oz

Converter

Common amounts in cups

Scale:

16 cups = 128 fl oz

Fluid ounces: 128 fl oz
Cups: 16
Tablespoons: 256
Teaspoons: 768
Milliliters: 3,785 mL
Measure with: 16 cups

Other cup standards

US cups: 16 · nutrition-label cups (240 mL): 15.773 · metric cups (250 mL): 15.142 · UK fluid ounces: 133.23

US customary cup = 236.6 mL

A US gallon is 16 cups. A half gallon is 8 cups, a quarter gallon (1 quart) is 4 cups, and 1 1/2 gallons is 24 cups. Each cup is 8 fl oz, which is how the gallon reaches 128 fl oz.

The common water goal of eight 8 oz glasses a day adds up to 64 fl oz, half a gallon. In a recipe, a gallon of stock or iced tea is four fills of a 4-cup measuring cup.

Gallons to cups
Gallons	Cups	Fluid ounces	Quarts
1/4	4	32	1
1/2	8	64	2
3/4	12	96	3
1	16	128	4
1 1/2	24	192	6
2	32	256	8
3	48	384	12
5	80	640	20

Cups to gallons
Cups	Gallons	Quarts
1 cup	0.063	0.25
2 cups	0.125	0.5
4 cups	0.25	1
6 cups	0.375	1.5
8 cups	0.5	2
10 cups	0.625	2.5
12 cups	0.75	3
16 cups	1	4
20 cups	1.25	5
24 cups	1.5	6
32 cups	2	8
48 cups	3	12
64 cups	4	16

US liquid measures
Unit	Quarts	Pints	Cups	Fluid ounces	mL
1 gallon	4	8	16	128	3,785
1 quart	1	2	4	32	946
1 pint	0.5	1	2	16	473
1 cup	0.25	0.5	1	8	237
1 fl oz	0.0313	0.0625	0.125	1	30

Cups in part of a gallon

1/4 gallon: 4 cups (1 quart)
1/2 gallon: 8 cups (2 quarts, 64 fl oz)
3/4 gallon: 12 cups (3 quarts)
1 gallon: 16 cups (4 quarts, 128 fl oz)

For the same gallon in fluid ounces, see ounces in a gallon.

Questions

How many cups in a gallon?

16 US cups.

How many cups in a half gallon?

8 cups, or 64 fl oz.

How many cups in a gallon of water?

16 cups. Water follows the same volume units as any other liquid.

How many cups in a UK gallon?

About 19.2 US cups, since an imperial gallon is 4.546 liters.

By Alton Vieira · Updated October 31, 2026. Sources: US customary units: NIST Handbook 44. How we calculate.