Updated 31 July 2026 · Written by Sofia Romano
There are 128 fluid ounces in a US gallon. A gallon breaks down into 4 quarts, 8 pints or 16 cups, and since each cup holds 8 fluid ounces, that comes to 128 ounces in total. Half a gallon is 64 fluid ounces.
1 gallon = 128 fluid ounces = 16 cups = 8 pints = 4 quarts.
How It Adds Up
A gallon contains 16 cups, and each cup is 8 fluid ounces, so 16 times 8 gives 128 fluid ounces. Working down, a half gallon is 64 ounces, a quart is 32 ounces and a pint is 16 ounces.
Handy for Big Batches
This matters for large drinks and recipes. A gallon of iced tea or punch is 128 fluid ounces, so you can scale a per-ounce recipe up to fill a gallon container easily.
Gallon Conversions
| Unit | Fluid ounces |
|---|---|
| 1 gallon | 128 oz |
| 1/2 gallon | 64 oz |
| 1 quart | 32 oz |
| 1 pint | 16 oz |
| 1 cup | 8 oz |
Frequently Asked Questions
How many ounces in half a gallon?
There are 64 fluid ounces in half a US gallon, since a full gallon holds 128.
How many 8 oz cups are in a gallon?
Sixteen. A gallon is 128 fluid ounces, and 128 divided by 8 is 16 cups.
