Convert US gallons to US fluid ounces
1 gal = 128 fl oz. Change the amount below, or read the formula and the reference table further down.
1 US gallon equals
US fluid ounces
1 gal = 128 fl oz
The formula
US gallons and US fluid ounces both measure volume from the same zero, so a single multiplier does the job.
fl oz = gal × 128
Going the other way? Convert US fluid ounces to US gallons.
US gallons to US fluid ounces table
Common values, rounded for reading.
| US gallons (gal) | US fluid ounces (fl oz) |
|---|---|
| 1 | 128 |
| 2 | 256 |
| 3 | 384 |
| 4 | 512 |
| 5 | 640 |
| 6 | 768 |
| 7 | 896 |
| 8 | 1,024 |
| 9 | 1,152 |
| 10 | 1,280 |
| 15 | 1,920 |
| 20 | 2,560 |
| 25 | 3,200 |
| 30 | 3,840 |
| 40 | 5,120 |
| 50 | 6,400 |
| 75 | 9,600 |
| 100 | 12,800 |
| 250 | 32,000 |
| 500 | 64,000 |
| 1,000 | 128,000 |
Questions people ask
- How many US fluid ounces are in a US gallon?
- One US gallon equals 128 US fluid ounces.
- How do I convert US gallons to US fluid ounces by hand?
- Multiply the number of US gallons by 128. For a rough check, 128 is close enough for most everyday use.
- What is 1 US gallon in US fluid ounces?
- 1 US gallon is 128 US fluid ounces.
Calcuit generates this page from a unit table, so the factors here match every other page on the site.