# Cubic feet to US gallons (ft³ to gal (US))

> Convert cubic feet to US gallons: 1 ft³ = 7.48052 gal (US). Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `cubic-feet-to-gallons` · Quantity: Volume (`volume`, base unit L) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/cubic-feet-to-gallons · This document: https://tttkmbb.com/conversion/cubic-feet-to-gallons.md · JSON: https://tttkmbb.com/conversion/cubic-feet-to-gallons.json (add `?value=` for a result)

## Formula

- `1 ft³ = 7.48052 gal (US)`
- `US gallons = cubic feet × 7.480519481`
- Reverse: `cubic feet = US gallons × 0.1336805556`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 ft³ = 37.4026 gal (US)
- 12.5 ft³ = 93.5065 gal (US)
- 100 ft³ = 748.052 gal (US)

## Conversion table

| Cubic feet (ft³) | US gallons (gal (US)) |
| --- | --- |
| 1 | 7.48052 |
| 2 | 14.961 |
| 3 | 22.4416 |
| 4 | 29.9221 |
| 5 | 37.4026 |
| 6 | 44.8831 |
| 7 | 52.3636 |
| 8 | 59.8442 |
| 9 | 67.3247 |
| 10 | 74.8052 |
| 15 | 112.208 |
| 20 | 149.61 |
| 25 | 187.013 |
| 30 | 224.416 |
| 40 | 299.221 |
| 50 | 374.026 |
| 75 | 561.039 |
| 100 | 748.052 |
| 200 | 1496.1 |
| 250 | 1870.13 |
| 500 | 3740.26 |
| 1000 | 7480.52 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=ft3&to_unit=gal_us` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"ft3","to_unit":"gal_us"}`
- All volume units: https://tttkmbb.com/api/v1/units?quantity=volume · full converter: [Volume Converter](https://tttkmbb.com/conversion/volume.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many US gallons are in one cubic foot?**

1 ft³ = 7.48052 gal (US). The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert cubic feet to US gallons?**

Multiply the value in cubic feet by 7.480519481: US gallons = cubic feet × 7.480519481. For example, 5 ft³ = 37.4026 gal (US).

**How do I convert US gallons back to cubic feet?**

Multiply by the inverse factor 0.1336805556 (cubic feet = US gallons × 0.1336805556), or use the US gallons-to-cubic feet page.

## Related conversions

- [US gallons to cubic feet](https://tttkmbb.com/conversion/gallons-to-cubic-feet.md) (reverse)
- [Liters to US gallons](https://tttkmbb.com/conversion/liters-to-gallons.md)
- [US gallons to Liters](https://tttkmbb.com/conversion/gallons-to-liters.md)
- [Milliliters to US fluid ounces](https://tttkmbb.com/conversion/ml-to-fl-oz.md)
- [US fluid ounces to Milliliters](https://tttkmbb.com/conversion/fl-oz-to-ml.md)
- [Liters to Milliliters](https://tttkmbb.com/conversion/liters-to-ml.md)
- [Milliliters to Liters](https://tttkmbb.com/conversion/ml-to-liters.md)
- [US cups to Milliliters](https://tttkmbb.com/conversion/cups-to-ml.md)
- [Milliliters to US cups](https://tttkmbb.com/conversion/ml-to-cups.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)