**How many ounces in a gallon of water?** A **gallon** contains 128 **ounces**. In terms of metric system, 1 gallon of water is equal to 160 fluid ounces. How many ounces in a half gallon? Itâ€™s answer is there are 64 fluid ounces in a half gallon. So the full gallon has 128 fluid ounces and the half gallon has 64 fl oz

**The U.S and U.K Imperial measurement system**

UK Imperial and the US system (a variation of the Imperial system). These were probably the most common due to their advancement in technology, growth of economy and population.

1 fluid Gallon = 4.54609 x 35.1951 = 160 ounces

**Ounces to gallon conversion**

The ounce to gallon conversion was a long debate before the standardization if these units, but now a days its not a big deal. There are two different measurements system going on in world right now. One is imperial British measurement system

**How many ounces in a half gallon of water?**

How many ounces in a half gallon of water is simple, we know the answer of how many ounces in a half gallon 2 have. There are 64 fl oz in half gallon of water.

How many oz in a water bottle? 1 well the answer is 128 fluid ounces equals in 1 gallon of water.

Also 160 Imperial liquid ounces equals 1 Imperial gallon. The Imperial gallon is bigger than U.S gallon.