How many ounces are in a gallon? In the US customary system, there are 128 fluid ounces in one gallon. This conversion refers to fluid ounces, which measure volume, not ounces of weight. One US gallon is also equal to 4 quarts, 8 pints, or 16 cups. Whether you are measuring water, milk, honey, gasoline, paint, or another liquid, the volume conversion remains the same: 1 gallon = 128 fl oz.
This guide explains how to convert gallons to ounces, ounces to gallons, and other common kitchen and household measurements. It also includes helpful conversion charts for US and Imperial measurements so you can quickly find the answer you need.
What is a gallon? What is an ounce? A gallon and a fluid ounce are both units used to measure volume. In everyday American cooking, baking, and grocery measurements, gallons and fluid ounces are part of the US customary system. The British Imperial system also uses gallons and fluid ounces, but the values are different from US measurements.
Here is a quick kitchen conversion chart for converting 1 gallon to ounces across different measurement systems:
| Unit of Measurement | US Fluid Ounces (fl oz) | Imperial Fluid Ounces | Liters (litres) |
|---|---|---|---|
| 1 US Liquid Gallon (customary) | 128 | 133.228 | 3.78541 |
| 1 US Dry Gallon (customary) | 148.947 | 155.0301 | 4.40488 |
| 1 Imperial UK Gallon (international) | 153.722 | 160 | 4.54609 |
US customary measurements are the standard units most commonly used in American home cooking and baking. Unless otherwise noted, this article refers to US liquid gallons and US fluid ounces.
Many countries, including Canada and the United Kingdom, often use liters for liquid measurements. However, older Imperial measurements may still appear in some contexts. Because US and Imperial gallons are not the same size, it is important to check which system a recipe or label is using before converting.
How many ounces of water should I drink in a day?
Knowing how many fluid ounces are in a gallon can be useful when tracking daily water intake. General fluid intake recommendations vary, but the National Academy of Medicine gives these approximate daily intake guidelines:
- Men: 13 cups; 104 ounces; 0.8125 gallons; 3.076 liters
- Women: 9 cups; 72 ounces; 0.5625 gallons; 2.129 liters
These are general recommendations, not individual medical advice. The amount of water a person needs can vary based on several factors, including:
- Physical activity level
- Body size
- Exposure to very hot, cold, or dry climates
- Illness, including fever, vomiting, or diarrhea
- Alcohol use
- Use of certain medications, especially diuretics
- Pregnancy or breastfeeding
How many ounces in a gallon?
To convert gallons to fluid ounces, use this simple formula:
1 gallon = 128 fluid ounces
The conversion ratio is:
Gallons × 128 = Fluid ounces
Or
Fluid ounces ÷ 128 = Gallons
For example, to convert 1 fluid ounce to gallons:
1 ÷ 128 = 0.0078125 gallon
That means one fluid ounce equals 0.0078125 gallon, or 1/128 of a gallon. For most everyday conversions, the key number to remember is simple: one US gallon contains 128 fluid ounces.
Ounces in a Gallon Chart
Use this gallons to ounces conversion table for US customary liquid measurements:
| Gallons (gal) | Fluid Ounces (fl oz) |
|---|---|
| ¼ | 32 |
| ½ | 64 |
| 3/4 | 96 |
| 1 | 128 |
| 2 | 256 |
| 3 | 384 |
| 4 | 512 |
| 5 | 640 |
| 6 | 768 |
| 7 | 896 |
| 8 | 1024 |
| 9 | 1152 |
| 10 | 1280 |
| 11 | 1408 |
| 12 | 1536 |
| 13 | 1664 |
| 14 | 1792 |
| 15 | 1920 |
| 16 | 2048 |
| 17 | 2176 |
| 18 | 2304 |
| 19 | 2432 |
| 20 | 2560 |
| 21 | 2688 |
Here is the Imperial gallons to Imperial fluid ounces conversion chart:
| Imperial Gallons | Imperial Fluid Ounces |
|---|---|
| ¼ | 40 |
| ½ | 80 |
| 3/4 | 120 |
| 1 | 160 |
| 2 | 320 |
| 3 | 480 |
| 4 | 640 |
| 5 | 800 |
| 6 | 960 |
| 7 | 1120 |
| 8 | 1280 |
| 9 | 1440 |
| 10 | 1600 |
| 11 | 1760 |
| 12 | 1920 |
| 13 | 2080 |
| 14 | 2240 |
| 15 | 2400 |
| 16 | 2560 |
| 17 | 2720 |
| 18 | 2880 |
| 19 | 3040 |
| 20 | 3200 |
| 21 | 3360 |
Half Gallon – Ounces Conversion
To convert a half gallon to ounces, use the standard formula:
Gallons × 128 = Fluid ounces
Or
0.5 × 128 = 64 fluid ounces
A half gallon contains 64 fluid ounces.
How many ounces in a half gallon?
There are 64 fluid ounces in a half gallon.
Is 64 oz the same as 1 gallon?
No. In US customary measurements, 64 fluid ounces equals ½ gallon. One full gallon equals 128 fluid ounces.
Is 32 oz half a gallon?
No. 32 fluid ounces equals ¼ gallon. A half gallon contains 64 fluid ounces.
How many liters in a gallon?
There are approximately 3.78541 liters in one US liquid gallon.
How many ounces in a liter?
There are approximately 33.814 US fluid ounces in one liter.
How many ounces in a cup?
There are 8 fluid ounces in one US customary cup.
How many ounces in a quart?
There are 32 fluid ounces in one US liquid quart.
How many cups in a gallon?
There are 16 US customary cups in one US gallon.
How many ml in a gallon?
There are approximately 3785.41 milliliters in one US liquid gallon.
How many ounces in a pound?
There are 16 ounces in a pound. This is a weight measurement, not a volume measurement. Fluid ounces measure volume, while ounces and pounds measure weight.
How many gallons is 50 ounces?
50 fluid ounces equals approximately 0.390625 gallon.
96 oz equals how many gallons?
96 fluid ounces equals 0.75 gallon, or ¾ gallon.
How many ounces is 1.5 gallons?
1.5 US gallons equals 192 fluid ounces.
How many ounces is 2 gallons?
There are 256 fluid ounces in 2 gallons.
How many oz is 3 gallons?
There are 384 fluid ounces in 3 gallons.
How many oz in 4 gallons?
There are 512 fluid ounces in 4 gallons.
How many ounces in 5 gallons?
There are 640 fluid ounces in 5 gallons.
How many ounces in a 55 gallon drum?
There are 7040 fluid ounces in a 55 gallon drum.
How many ounces in a gallon of water?
There are 128 fluid ounces in a gallon of water. This is the same volume conversion used for other liquids measured by the US gallon.
Water Bottle Sizes Conversions
Use this ounces, gallons, and liters conversion table for common water bottle sizes:
| Ounces (oz) | Gallons (gal) | Liters (L) |
|---|---|---|
| 6 | 0.046875 | 0.177441 |
| 8 | 0.0625 | 0.236588 |
| 16 | 0.125 | 0.473176 |
| 16.9 | 0.1320312 | 0.4997926 |
| 24 | 0.1875 | 0.709765 |
| 32 | 0.25 | 0.946353 |
| 64 | 0.5 | 1.89271 |
How many 8 ounce glasses does it take to make a gallon?
It takes 16 glasses of 8 fluid ounces each to make one gallon.
How many gallons is 8 glasses?
If each glass holds 8 fluid ounces, 8 glasses equal 64 fluid ounces, or ½ gallon. If each glass holds 16 fluid ounces, 8 glasses equal 128 fluid ounces, or one gallon.
How many fluid ounces is 8 glasses of water?
Eight 8-ounce glasses of water equal 64 fluid ounces. Eight 16-ounce glasses equal 128 fluid ounces, which is one gallon.
How many 16 oz bottles make up a gallon of water?
It takes 8 bottles of 16 fluid ounces each to make one gallon of water. It takes 4 bottles of 16 fluid ounces each to make a half gallon.
How many 6 oz glasses are in a gallon?
There are 21.333 six-ounce glasses in one gallon, which is the same as 21 1/3 glasses.
How many 16.9 oz in a gallon?
There are approximately 7.574 bottles of 16.9 fluid ounces in one gallon.
FAQs
How many ounces in a gallon of milk?
There are 128 fluid ounces in one gallon of milk. This is a volume measurement. One gallon of milk weighs approximately 8.6 pounds, or 137.6 ounces by weight.
How many ounces in a gallon of gas?
There are 128 fluid ounces in one gallon of gasoline. One gallon of gas weighs about 6 pounds, or 96 ounces by weight. The exact weight can vary depending on the type of gasoline and additives.
How many ounces in a gallon of paint?
There are 128 fluid ounces in one gallon of paint by volume. Paint may weigh 6 to 12 pounds per gallon, so the weight in ounces can vary significantly.
How many ounces in a gallon of ice cream?
There are 128 fluid ounces in a gallon of ice cream. By weight, ice cream is about 5 pounds per gallon, or around 80 ounces.
How many ounces are in a gallon of honey?
There are 128 fluid ounces in a gallon of honey. Honey weighs about 12 pounds per gallon, or approximately 192 ounces by weight.
How many ounces are in a gallon of baked beans?
There are 128 fluid ounces in one gallon of baked beans by volume. The exact weight in ounces depends on the recipe and density.
How many ounces in a gallon ziploc bag?
A gallon storage bag can hold about 128 fluid ounces by volume.
How many ounces in a gallon in Canada?
Canada uses the metric system, so liquids such as milk and gasoline are usually measured in liters. If using the Imperial system, one Imperial gallon contains 160 Imperial fluid ounces.
More Measurement Conversions
Here are a few additional measurement conversions that are helpful for cooking, baking, and everyday liquid measurements:
- How many tablespoons in ¼ cup
- 8 ounces to cups conversion
- How much is 3 oz chicken