Water conversion
How many ounces of water are in a gallon?
Answer
A US gallon of water is 128 fluid ounces, which is about 3.8 litres. That's roughly eight 16 oz glasses doubled — or about 7.5 of the common 16.9 oz bottles. A full gallon a day is well above most people's needs unless they're very large or very active.
1 US gallon = 128 fl oz = 3.785 litres. (A UK imperial gallon is larger, at 160 imperial fluid ounces.)
| Gallons | Fluid ounces | Litres |
|---|---|---|
| 0.25 | 32 | 0.9 |
| 0.5 | 64 | 1.9 |
| 0.75 | 96 | 2.8 |
| 1 | 128 | 3.8 |
A gallon is about double a typical daily goal — see your real number first.
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Frequently asked
How many ounces in a gallon of water?
A US gallon of water contains 128 fluid ounces (3.785 litres).
Is a gallon of water a day too much?
For most people a gallon (3.8 litres) is more than needed. It isn't dangerous if spread out, but drinking very large amounts quickly can dilute your blood sodium, so pace it and don't exceed about 1 litre per hour.