Convert US gallons to US fluid ounces
1 US gallon is 128 fl oz. One US gallon is exactly 128 US fluid ounces.
US fluid ounces
128 fl oz
- US gallons × 128
value * 128128 fl oz
1 US gallon in every volume unit
| Unit | Value | Exact factor |
|---|---|---|
| US teaspoons | 768 tsp | × 768 |
| US tablespoons | 256 tbsp | × 256 |
| US fluid ounces | 128 fl oz | × 128 |
| US cups | 16 cup | × 16 |
| US pints | 8 pt | × 8 |
| US quarts | 4 qt | × 4 |
| US gallons (as entered) | 1 gal | — |
| millilitres | 3,785.411784 ml | × 3,785.411784 |
| litres | 3.785411784 L | × 3.785411784 |
Factors are entered by hand from NIST Handbook 130 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How to convert
- 1.Take the measurement in US gallons.
- 2.Multiply by 128 — that is how many US fluid ounces fit in one US gallon.
- 3.To go back the other way, divide by 128, or multiply by 0.0078125.
US gallons to US fluid ounces conversion table
| US gallons | US fluid ounces |
|---|---|
| 1 gal | 128 fl oz |
| 2 gal | 256 fl oz |
| 3 gal | 384 fl oz |
| 4 gal | 512 fl oz |
| 5 gal | 640 fl oz |
| 6 gal | 768 fl oz |
| 7 gal | 896 fl oz |
| 8 gal | 1,024 fl oz |
| 9 gal | 1,152 fl oz |
| 10 gal | 1,280 fl oz |
| 12 gal | 1,536 fl oz |
| 15 gal | 1,920 fl oz |
| 20 gal | 2,560 fl oz |
| 25 gal | 3,200 fl oz |
| 50 gal | 6,400 fl oz |
| 100 gal | 12,800 fl oz |
The two units
- US gallon (gal)
- Exactly 231 cubic inches. The imperial gallon is 4.546 litres, so US and UK fuel economy figures are not comparable.
- US fluid ounce (fl oz)
- Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly. The imperial fluid ounce is a different unit at exactly 28.4130625 ml, so a UK recipe calling for 10 fl oz means 284 ml and a US one means 296 ml. It is also a volume, not a weight: an ounce of flour is not a fluid ounce of flour.
Questions people actually ask
- How many US fluid ounces are in a US gallon?
- 128. Exactly one 128th of a US gallon, which makes it 29.5735295625 ml exactly. The imperial fluid ounce is a different unit at exactly 28.4130625 ml, so a UK recipe calling for 10 fl oz means 284 ml and a US one means 296 ml. It is also a volume, not a weight: an ounce of flour is not a fluid ounce of flour.
- How do I convert US fluid ounces back to US gallons?
- Divide by 128, or multiply by 0.0078125 — they are the same operation.
Other volume conversions
US fluid ounces to US gallons — the same conversion the other way.