conversions
Ounces to Gallons
Last updated: June 19, 2026
A volume conversion utility that converts fluid ounces (fl oz) to US gallons (gal). Based on the US customary system, there are exactly 128 fluid ounces in a standard liquid gallon, making one fluid ounce equal to 1/128 of a gallon.
Convert ounces to gallons instantly. Read the conversion answers, the mathematical formula, and browse the reference lookup table.
Quick Answer
Convert fluid ounces to gallons. There are exactly 128 fluid ounces in 1 US gallon.
Ounces to Gallons
Bidirectional Fluid Ounces (fl oz) and Gallons (gal) Converter
Compute exact conversions between fluid ounces (fl oz) and gallons (gal).
Bidirectional live updates. Enter a number in either field to convert instantly.
Answer
1 gal
128 fl oz = 1 gal
Ounces to Gallons Reference Table
| Fluid Ounces (fl oz) | Gallons (gal) | Description |
|---|---|---|
| 8 fl oz | 0.06 gal | One standard cup |
| 16 fl oz | 0.125 gal | One pint |
| 32 fl oz | 0.25 gal | One quart |
| 64 fl oz | 0.50 gal | Half of a gallon |
| 128 fl oz | 1.00 gal | Exactly one gallon |
| 256 fl oz | 2.00 gal | Exactly two gallons |
Examples
128 fl oz
1 gal
How it works
To convert fluid ounces (fl oz) to gallons (gal), perform the following calculation:
Formula
gal = fl oz ÷ 128
Method
Divide the fluid ounces value by 128 to get the equivalent volume in gallons.
Understanding Ounces to Gallons Conversions
Fluid ounces measure smaller liquid volumes, while gallons are used for bulk measurements. In standard US volume terminology, a gallon consists of 128 fluid ounces. This bidirectional conversion is useful for tracking daily water intake targets, shipping liquids, and mixing chemical solutions in correct proportions.
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Frequently asked questions
Divide the fluid ounces value by 128.
There are exactly 128 fluid ounces in a single standard US liquid gallon.
Divide by 128 (e.g. 64 ounces ÷ 128 = 0.5 gallons).
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