Gallons to Cups Converter
Convert gallons to cups in US customary units. Enter any number of gallons — whole or fractional like 0.5 — and get exact cups, quarts, pints, and fluid ounces.
Example: with Gallons (US) 1 → Cups: 16 cups.
- In quarts4 quarts
- In pints8 pints
- In fluid ounces128 fl oz
Computed by the calculator below using its default values. Change any input to see your own numbers.
A US gallon is exactly 16 cups. The chain is 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces.
The US gallon, split into cups
US kitchen volumes nest in neat factors. A gallon holds 4 quarts, each quart holds 2 pints, each pint holds 2 cups, and each cup holds 8 fluid ounces. Multiply them together and a gallon is exactly 16 cups or 128 fluid ounces. Because these are definitions, the conversion is exact — no density, no substance, no rounding needed.
That makes the fractions easy too: half a gallon is 8 cups, a quarter gallon is 4 cups, and a single cup is one-sixteenth of a gallon.
US cups versus everyone else
This tool uses the US customary cup of 8 fluid ounces, about 236.6 mL. A metric cup is 250 mL and an older UK cup roughly 284 mL, so recipes from Australia or Britain will not line up exactly. Expect a few percent difference per cup, which adds up across a full gallon.
For water and most thin liquids the volume math here is all you need. For dry ingredients measured by weight, use a grams or ounces converter instead.
How it’s calculated
US customary volume, exact by definition: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces. Cups = gallons × 16, quarts = gallons × 4, pints = gallons × 8, fluid ounces = gallons × 128.
Uses the US customary cup of 8 fl oz. Metric (250 mL) and UK cups differ, so imported recipes will not match exactly.
US gallon volume equivalents
| Gallons | Quarts | Pints | Cups | Fluid oz |
|---|---|---|---|---|
| 0.25 | 1 | 2 | 4 | 32 |
| 0.5 | 2 | 4 | 8 | 64 |
| 1 | 4 | 8 | 16 | 128 |
| 2 | 8 | 16 | 32 | 256 |
| 5 | 20 | 40 | 80 | 640 |
US customary volume; 1 US gallon = 231 cubic inches = 3.785411784 L by definition.
Common mistakes
- Using a US cup for a metric-cup (250 mL) recipe — they differ by about 5 percent.
- Confusing dry and liquid measure; this tool is liquid volume, not weight.
- Forgetting a US gallon (16 cups) is smaller than a UK gallon (about 18.2 US cups).
- Mixing fluid ounces (volume) with ounces of weight.
Frequently asked questions
How many cups are in a gallon?
A US gallon holds exactly 16 cups. That comes from 128 fluid ounces per gallon divided by 8 fluid ounces per cup.
How many cups in a half gallon?
Eight cups. Half of 16 cups is 8, which is also 4 pints or 64 fluid ounces.
What is the formula for gallons to cups?
Multiply gallons by 16. For quarts multiply by 4, for pints by 8, and for fluid ounces by 128.
Are US and UK cups the same?
No. This tool uses the US cup of 8 fluid ounces (236.6 mL); a metric cup is 250 mL and the older UK cup is about 284 mL, so results differ for imported recipes.