# How do I convert gallons to cups?

Converts gallons (gal) to cups (cup) and back, with the exact unit definitions.

- Page: https://www.acalculator.org/convert/gallons-to-cups
- JSON spec: https://www.acalculator.org/convert/gallons-to-cups.json
- Version: 881d1dc1b527

## Default answer

Example with the default inputs (Gallons (gal) 1): 1 gal = 16 cup.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Gallons (gal) | The amount in gallons to convert. |
| result | Cups (cup) | The same amount in cups. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Gallons (gal) | The amount in gallons to convert. |
| result | Cups (cup) | The amount in cups. |

## Method

cup = gal × 16

## Assumptions

- 1 gallon = 16 cups, from the exact definitions in NIST SP 811.
- Cups, ounces, tablespoons, pints, quarts, and gallons are US customary units: 1 US cup is 8 US fluid ounces.
- The answer shows at most 6 decimal places; the calculation keeps full precision.

## Worked examples

1. value = 1 gives result = 16. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.
2. value = 3 gives result = 48. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.
3. result = 48 gives value = 3. Source: exact unit definitions in NIST SP 811 (2008), Appendix B.8.

## FAQ

### How many cups are in a gallon?

1 gallon is 16 cups, from the exact unit definitions (NIST SP 811).

### How do I convert gallons to cups?

Multiply by 16: cup = gal × 16. For example, 1 gal × 16 = 16 cup.

### How do I convert cups back to gallons?

Multiply by 0.0625, or type the cups into the second box and the converter works it out. 1 cup is 0.0625 gallons.

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8. https://www.nist.gov/pml/special-publication-811