How many ounces in a gallon?
1 gallon = 128 fl oz
16 cups · 8 pints · 4 quarts · 3.785 liters
Converter
Other cup standards
US cups: 16 · nutrition-label cups (240 mL): 15.773 · metric cups (250 mL): 15.142 · UK fluid ounces: 133.23
A US gallon is 128 fl oz, which is 4 quarts, 8 pints or 16 cups, about 3.79 liters. The plastic milk jug is the gallon most people picture, and the half-gallon carton beside it holds 64 fl oz, or 8 cups.
This question often comes up when tracking water. A common 16.9 fl oz (500 mL) bottle goes into a gallon about 7 1/2 times, so 8 bottles slightly overshoot. Measured in 8 fl oz glasses, 16 of them fill a gallon.
| Gallons | Cups | Fluid ounces | Liters | 16.9 fl oz bottles |
|---|---|---|---|---|
| 0.25 | 4 | 32 | 0.946 | 1.9 |
| 0.5 | 8 | 64 | 1.893 | 3.8 |
| 0.75 | 12 | 96 | 2.839 | 5.7 |
| 1 | 16 | 128 | 3.785 | 7.6 |
| 1.5 | 24 | 192 | 5.678 | 11.4 |
| 2 | 32 | 256 | 7.571 | 15.1 |
| 3 | 48 | 384 | 11.356 | 22.7 |
| 5 | 80 | 640 | 18.927 | 37.9 |
| 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 |
| Measure | US | UK |
|---|---|---|
| 1 cup | 237 mL | 250 mL (metric cup) |
| 1 pint | 473 mL | 568 mL |
| 1 quart | 946 mL | 1,137 mL |
| 1 gallon | 3,785 mL | 4,546 mL |
Breaking a gallon down
- 1 gallon = 4 quarts = 128 fl oz
- 1/2 gallon = 2 quarts = 64 fl oz
- 1/4 gallon = 1 quart = 32 fl oz
- 1 quart = 2 pints = 4 cups
More in cups in a quart and cups in a pint.
US gallon vs. UK gallon
An imperial (UK) gallon is 4.546 liters, about 153.7 US fl oz, roughly a fifth more than a US gallon. US recipes and US product labels always mean the 3.785 liter US gallon.
Questions
How many 16.9 oz water bottles make a gallon?
About 7 1/2 (7.57). Eight bottles add up to a little more than a gallon.
How many cups in a gallon?
16 cups.
How many mL in a gallon?
About 3,785 mL, or 3.785 liters.
How much does a gallon of water weigh?
About 8.3 lb, or about 133 oz by weight.
Sources: US customary units: NIST Handbook 44. How we calculate.