Shipping over $50
You are filling a gallon jug, and the bottle in your hand says ounces. Or a recipe says quarts and the carton says cups.
Here is the whole set, in one place.
One US gallon holds 128 fluid ounces. A half gallon is 64 oz. A quart is 32 oz, a pint is 16 oz, and a cup is 8 oz. The US gallon is not the same as the imperial gallon, which holds 160 imperial fluid ounces.
How many ounces are in a gallon?
128 fluid ounces, in the US.
The rest of the scale follows from that. A gallon splits into 4 quarts, 8 pints or 16 cups, and every one of those is a whole number.
| Amount | Fluid ounces | Cups | Liters |
|---|---|---|---|
| Quarter gallon (1 quart) | 32 oz | 4 | 0.95 |
| Half gallon | 64 oz | 8 | 1.89 |
| One gallon | 128 oz | 16 | 3.79 |
| Two gallons | 256 oz | 32 | 7.57 |
How many ounces are in a half gallon?
64 fluid ounces.
That is 8 cups, or 2 quarts, or a little under 1.9 liters. It is also the number most people mean when they say “a big jug”.
Worth knowing: a half gallon of milk in the store is exactly this. 64 oz.
Is a gallon always 128 ounces?
No, and this is where people get caught out.
A US gallon is 128 US fluid ounces. An imperial gallon, still used in the UK and in some Commonwealth recipes, is 160 imperial fluid ounces. The imperial gallon is about a fifth larger.
So a British recipe calling for a gallon is asking for more liquid than an American one.
The second trap is the word ounce itself. A fluid ounce measures volume, an ounce measures weight, and they are not interchangeable. Water is close enough that people get away with it. Flour and honey are not.
How many cups are in a gallon?
16 cups.
A cup is 8 fl oz, so 16 of them make 128. Half a gallon is 8 cups, a quart is 4 cups, and a pint is 2.
Handy for cooking: if a recipe scales by the quart, you are scaling in fours.
How many liters is a gallon?
3.785 liters, rounded to 3.79 in most tables.
Going the other way, one liter is about 33.8 fluid ounces. That is why a 1 liter bottle from Europe reads as 34 oz on a US label. It is also why our largest bottle is 34 oz.
A half gallon is 1.89 liters. Two gallons is 7.57.
How many water bottles make a gallon?
It depends on your bottle, and the answer is usually smaller than people expect.
Here are our three sizes against a gallon. The single-use bottle is in there too, because that is the one most people picture.
| Bottle | Size | Refills to a gallon | Refills to a half gallon |
|---|---|---|---|
| Vacuum Insulated Water Bottle | 17 oz | about 7.5 | about 3.8 |
| Vacuum Insulated Water Bottle | 25 oz | about 5 | about 2.6 |
| Vacuum Insulated Water Bottle | 34 oz | about 3.75 | about 1.9 |
| Double Vacuum Insulated Water Bottle | 12 oz | about 10.7 | about 5.3 |
| Standard single-use bottle | 16.9 oz | about 7.6 | about 3.8 |
Our bottles hold 25 hours cold and 13 hours hot, with no preheating. The Double Vacuum comes in 12 to 34 oz. Its click lid is plastic, and we say so plainly. The body is steel, the lid is not.
Not sure which size suits you? We wrote a short guide on choosing a stainless steel water bottle.
Quick reference: ounces to gallons
The other direction, for when the number on the label is the ounces.
| Fluid ounces | Gallons | Cups |
|---|---|---|
| 8 oz | 1/16 | 1 |
| 16 oz | 1/8 | 2 |
| 32 oz | 1/4 | 4 |
| 64 oz | 1/2 | 8 |
| 128 oz | 1 | 16 |
What if you are measuring food, not water?
Then the container matters more than the conversion.
Our insulated food jar comes in 18, 24 and 34 oz. That is roughly two, three or four cups. A 24 oz jar is a normal portion of soup. It holds 14 hours hot, with no preheating, if you rinse it hot, fill it full and keep it closed.
Questions people ask
How many 16.9 oz bottles make a gallon?
About 7.6. The 16.9 oz bottle is the standard single-use size, and it is 500 milliliters relabeled for the US. Seven of them leaves you about 10 oz short of a gallon. That is why the honest answer is a fraction.
Is a gallon of water a day too much?
For most adults it is more than the usual guidance. The reference figures for total water intake, from food and all drinks, sit below a gallon. We work through the numbers in how many water bottles you should drink a day.
How many ounces in a gallon of water specifically?
The same 128 fluid ounces. A gallon is a measure of volume, so it does not change with the liquid. What changes is the weight: a gallon of water weighs about 8.3 pounds, and a gallon of milk slightly more.
Why is a UK gallon different?
Because the two systems were defined separately. The imperial gallon was fixed to the volume of ten pounds of water. The US gallon kept an older wine measure of 231 cubic inches. That is 160 imperial fluid ounces against 128 US ones.
Keep the number handy
128 ounces to the gallon. 64 to the half. 16 cups either way.
If you are tracking a daily target, the easiest version is not math at all. Fill one bottle in the morning, know what it holds, and count refills. Our stainless steel water bottles come in 17, 25 and 34 oz, which makes the counting easy.
