How many ounces in an imperial gallon?
160 ounces equals one imperial gallon
There are approximately 153.722 U.S. fluid ounces in an Imperial gallon. Although Canada officially adopted the metric system shortly after 1970, some Imperial measurements, such as the gallon, are still in use. The Canadian government defines one gallon as consisting of exactly 160 Imperial ounces, and there are approximately 1.041 Imperial ounces in a U.S. fluid ounce. The U.S. liquid gallon consists of 128 U.S. fluid ounces, and there are approximately 1.201 U.S. liquid gallons…
There are 8 imperial pints in an imperial (British) gallon. An imperial pint is 20 ounces and an imperial gallon is 160 ounces. A US pint is 16 US ounces, so there are approximately 10 US pints in a British gallon (a US ounce is slightly larger than an imperial ounce; 1 US ounce = 1.041 imperial ounce approximately).
1 Gallon = 128 fluid ounces (volume not weight) That's a US gallon. An Imperial gallon is 160 ounces, but the ounces aren't the same size as US ounces. Nevertheless, an Imperial gallon is larger. Using litres and millilitres to measure volume solves this confusion. (Of course the US doesn't use Imperial gallons, but here in Canada we did prior to going metric.)
It depends on if you are using U.S. or Imperial form of an ounce, really. One Imperial ounce is 1/160th of a gallon and one U.S. ounce is 1/128th of a gallon. Take the U.S. ounce for example, and basic fraction math will state that it takes 128 ounces to form one gallon. Multiply this by 2 and you get your answer of 256 ounces. Long answer short: 256 U.S. ounces or 320 Imperial ounces.