---
title: "US gallons to Imperial fluid ounces converter"
description: "1 US gallon = 133.2279 imperial fluid ounces. Conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/gallons-to-imperial-fl-oz/
site: "At One Place"
---

# US gallons to imperial fluid ounces

**1 US gallon in imperial fluid ounces: 1 gal = 133.2279 imp fl oz**

imp fl oz = gal × 133.2278695

To convert US gallons to imperial fluid ounces, multiply by 133.2278695. The table below gives the values people look up most often, and the converter works for any number.

## US gallons to imperial fluid ounces table

*Common US gallon values converted to imperial fluid ounces.*

| US gallons | Imperial fluid ounces |
| --- | --- |
| 1 gal | 133.2279 |
| 2 gal | 266.4557 |
| 3 gal | 399.6836 |
| 4 gal | 532.9115 |
| 5 gal | 666.1393 |
| 10 gal | 1,332.2787 |
| 15 gal | 1,998.418 |
| 20 gal | 2,664.5574 |
| 25 gal | 3,330.6967 |
| 30 gal | 3,996.8361 |
| 40 gal | 5,329.1148 |
| 50 gal | 6,661.3935 |
| 75 gal | 9,992.0902 |
| 100 gal | 13,322.787 |
| 250 gal | 33,306.967 |
| 500 gal | 66,613.935 |
| 1,000 gal | 133,227.87 |

## How the conversion works

The relationship is imp fl oz = gal × 133.2278695. Both units measure volume, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.

> US gallon: US liquid gallon. The imperial gallon is about 20% larger.

## Common questions

### How many imperial fluid ounces are in one US gallon?

One US gallon equals 133.2279 imperial fluid ounces. imp fl oz = gal × 133.2278695.

### How do you convert US gallons to imperial fluid ounces?

Use imp fl oz = gal × 133.2278695. So 10 gal is 1,332.2787 imp fl oz.

### How many US gallons are in one imperial fluid ounce?

One imperial fluid ounce equals 0.0075059 US gallons, which is the reverse of the conversion above.

### Is there more than one kind of US gallon?

US liquid gallon. The imperial gallon is about 20% larger.

## Related pages

- [Imperial fluid ounces to US gallons](https://atoneplace.net/convert/imperial-fl-oz-to-gallons/)
- [US gallons to Liters](https://atoneplace.net/convert/gallons-to-liters/)
- [US gallons to Milliliters](https://atoneplace.net/convert/gallons-to-ml/)
- [US gallons to Cubic meters](https://atoneplace.net/convert/gallons-to-cubic-meters/)
- [US gallons to US quarts](https://atoneplace.net/convert/gallons-to-quarts/)
- [US gallons to US pints](https://atoneplace.net/convert/gallons-to-pints/)
- [US gallons to US cups](https://atoneplace.net/convert/gallons-to-cups/)
- [US gallons to US fluid ounces](https://atoneplace.net/convert/gallons-to-fl-oz/)
- [US gallons to Tablespoons](https://atoneplace.net/convert/gallons-to-tablespoons/)
- [US gallons to Teaspoons](https://atoneplace.net/convert/gallons-to-teaspoons/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)