# What is 1.5 gallons to cups?

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

- Page: https://www.acalculator.org/convert/1-point-5-gallons-to-cups
- JSON spec: https://www.acalculator.org/convert/1-point-5-gallons-to-cups.json
- Version: 8ec98adf53eb

## Default answer

Example with the default inputs (Gallons (gal) 1.5): 1.5 gal = 24 cups.

## 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, teaspoons, pints, quarts, and gallons are US customary units: 1 US cup is 8 US fluid ounces.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up; an answer of 1 billion or more shows at most 15 significant digits.

## 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

### What is 1.5 gallons in cups?

1.5 gal is 24 cups. The formula is cup = gal × 16.

### 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, 1.5 gal × 16 = 24 cups.

### 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: Factors for Units Listed Alphabetically (bold factors are exact), retrieved 2026-10-18. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8