This free converter changes US gallons (gal) to cups and back again, updating live as you type into either field. It is useful for scaling recipes, batching drinks, and reading water-cooler or jug capacities in everyday cup measures.
How it works
US customary volume units nest neatly: 1 gallon = 4 quarts, 1 quart = 2 pints, and 1 pint = 2 cups. That gives a fixed, exact relationship of 16 cups per gallon, so the converter uses:
cups = gallons × 16 (and gallons = cups ÷ 16)
Type in the gallons field and it multiplies by 16; type in the cups field and it divides by 16. Nothing is rounded for whole-number gallons, and results display up to 8 significant figures.
Example
Suppose a punch recipe makes 2.5 gallons and you want to know how many cups that is:
2.5 × 16 = 40 cups
So a 2.5-gallon batch fills forty standard cups — enough for roughly 20 servings at two cups each.
| US gallons (gal) | Cups |
|---|---|
| 0.25 gal | 4 cups |
| 0.5 gal | 8 cups |
| 1 gal | 16 cups |
| 2 gal | 32 cups |
| 5 gal | 80 cups |
All calculations run entirely in your browser — no data is sent to any server.