Gallon (US) to Fluid Ounce (US) (US gal to US fl oz)
Result
128 Fluid Ounce (US)
Formula
US fl oz = US gal × 128
1 US gal = 128 US fl oz, and 1 US fl oz = 0.0078125 US gal.
The litre is exactly 1 dm³ (0.001 m³). The US gallon is defined as 231 cubic inches, which makes it exactly 3.785411784 L; quarts, pints, cups and fluid ounces are fixed fractions of it.
Worked examples
- 1 US gal × 128 = 128 US fl oz
- 10 US gal × 128 = 1,280 US fl oz
- 100 US gal × 128 = 12,800 US fl oz
Common mistakes
- US and UK (imperial) measures share names but not sizes: the imperial gallon is 4.54609 L (20% larger), the imperial pint 568 mL and the imperial fluid ounce 28.41 mL.
- This converter uses US customary volumes. A US cup is 236.59 mL, a metric cup 250 mL, and US nutrition labels round a cup to 240 mL.
- US dry measures (dry pint, bushel) are a separate system and are not the same as liquid pints.
Gallon (US) to Fluid Ounce (US) table
| Gallon (US) (US gal) | Fluid Ounce (US) (US fl oz) |
|---|---|
| 1 | 128 |
| 2 | 256 |
| 5 | 640 |
| 10 | 1,280 |
| 20 | 2,560 |
| 50 | 6,400 |
| 100 | 12,800 |
| 1,000 | 128,000 |
The units
- Gallon (US) (US gal)
- The US liquid gallon: 231 cubic inches, exactly 3.785411784 L.
- Fluid Ounce (US) (US fl oz)
- One 128th of a US gallon: 29.5735295625 mL.
Sources for these factors
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
- 21 CFR 101.9 (nutrition labeling: household measure equivalents) — U.S. FDA / eCFR
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy