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How many ounces in a gallon?

by Sophie

Do you wonder how many ounces in a gallon of water or any other fluid? The math is simple and straightforward, but it baffles many. The liquid oz to gallon or gallon to oz conversion, however, can be tricky and involves a little math. Remember, all you need to do is understand some basic calculations or just come back here to use this calculator and to print the chart.

Some of the commonly found units of liquid measurement are ounces, liters, pints, quarts, and gallons. While it may seem confusing, but, I have a simple chart for you. And, we are going to discuss in detail about a gallon to ounces and other liquid measurements in this post.

Ounce to Gallon Convertor

Ounce to Gallon Converter

Type a value in the ounce field to convert the value to galoons:

Ounce to Gallons

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As per the US measurements system, a gallon equals to 128 ounces, 4 quarts, 8 pints, and even 16 cups. Here is a chart with details of liquid conversions. Feel free to download and print it. Or, just Pinit for later.

How Many Ounces in A Gallon?

Based on U.S. customary guides for liquid conversion, a gallon is equal to 128 ounces. Here is a brief outline.

The U.S.A Measurement:

1 fluid Gallon = 128 Ounces
1 Gallon (US, Fluid) = 3.785 liters
1 Liter = 33.814 Ounces (US fluid)
1 fluid Gallon = 3.785 x 33.814 = 128 ounces
Formula = 1 Ounce (OZ) = 0.0078125 Gallons (Gal)
or, 1 gallon = 128 ounces

The UK measurement:

1 Gallon = 160 Ounces
1 Gallon (UK, Fluid) = 4.54609 liters
1 Liter = 35.1951 ounces (UK fluid)
1 fluid Gallon = 4.54609 x 35.1951 = 160 ounces

How Do Both Systems Work?

Both the US and the UK liquid customary measurements systems take the fluids by volume and divide them into 4 parts. However, the major difference is the calculation. While the US measurements system says a gallon is 128 ounces, a UK system defines a gallon is 160 ounces. Now, there is a major difference here. Even though both systems use gallons, ounces, pints, and quarts, they use different volume measurements. To summarize this, the UK gallon is about 20% larger than the US gallon.

What is a Gallon?

A gallon is a volume measurement for liquid in the United States Customary Measurement system. The abbreviation for a gallon is “gal.”

What is a fluid ounce?

A Fluid ounce is another volume measure for liquid or dry mass in the United States Customary Measurement System. The symbol is “fl oz.”

How many fluid ounces in a gallon?

The U.S standard framework considers a gallon as the imperial unit of liquid volume. While liters and milliliters are common in the UK and Europe, here in the United States, the measurement is in gallons. In USA Customary context, gallons can be liquid or dry and are distinctive in sizes and imperial structure. When used in fluid, the abbreviation for gallon is always "gal."

The liquid ounce (as we have discussed in our previous post) is an imperial and U.S. customary volume unit, which applies to both dry and liquid or fluid. For instance, a cup equals to eight fluid ounces whereas a cup equals to the dry mass of the non-fluid item in the cup. In short, the fluid ounces are volume units and should never be mistaken with dry ounces which literally means mass or weight.

1 US Fluid Gallon = 128 US Fluid Ounces

How many gallons in a fluid ounce?

The formula just reverses here. To convert fluid ounces to gallons, divide the gallon value by 128.

1 US Fluid Ounce = 0.0078125 Fluid Gallon

How many imperial Fluid ounces in an imperial garden?

Based on the imperial system, there are 160 imperial fluid ounces in 1 imperial gallon. If you want to convert imperial gallons to fluid ounces, multiply the imperial gallon value by 160.

1 Imperial Gallon = 160 Imperial Fluid Ounces

How many imperial fluid ounces are in an imperial gallon?

As per the imperial system, one imperial ounce equals to 0.00625 imperial gallon.

1 Imperial Ounce = 0.00625 Imperial Gallon

Gallons (US) Ounces (US) Liters Gallons (UK) Ounces (UK) Liters
1 gal 128 3.785 L 1 gal 160 4.546  
2 gal 256 7.571 L 2 gal 320   9.092  
3 gal 384 11.356 L 3 gal 480   13.638  
4 gal 512 15.142 L 4 gal 640   18.184  
5 gal 640 18.927 L 5 gal 800   22.73  
6 gal 768 22.712 L 6 gal 960 27.277  
7 gal 896 26.498 L 7 gal 1120   31.823  
8 gal 1024 30.283 L 8 gal 1280   36.369  
9 gal 1152 34.069 L 9 gal 1440   40.915  
10 gal 1280 37.854 L 10 gal 1600   45.461  
11 gal 1408 41.64 L 11 gal 1760   50.007  
12 gal 1536 45.425 L 12 gal 1920   54.553  
13 gal 1664 49.21 L 13 gal 2080   59.099  
14 gal 1792 52.996 L 14 gal 2240   63.645  
15 gal 1920 56.781 L 15 gal 2400   68.191  

How Many Ounces Are In Half a Gallon?

The calculation of gallons to ounces stays the same. That means if a gallon is 128 ounces, half a gallon is 64 ounces and so on.

Gallons Ounces Gallons Ounces
1 128 1/16 8
1/2 64 1/32 4
1/4 32 1/64 2
1/8 16 1/128 1

How many ounces in a gallon of water?

If the conversion is from US gallon to ounces, there are 128 ounces in one gallon. To convert gallon to ounces then, multiply the number of gallons by 128. How about gallons to Ounces (OZ)? One ounce is equal to 0.0078125 gallons. That means if you want to change a thousand ounces to gallons, you multiply by 1000.

Water is life, and nothing would exist without water. It is highly recommended that you drink at least one gallon of water every day. Drinking water cures headaches, fatigue, joint pain, and much more. Drinking a gallon of water is sufficient, but a gallon is tough to calculate.

How many glasses of water in one gallon?

You only need to understand the capacity of one gallon to get this right. One gallon is equal to 128 ounces or 3.8 liters.

What is a gallon and what is a fluid ounce?

Gallon is a US Customary measurement systems volume unit while fluid ounce symbol “fl oz.” is an imperial measurement system in the US systems volume unit. One gallon of water has 128 fluid ounces. One fluid gallon is equal to 128 fluid ounces. Mostly, liquid measurements are in ounces, which strongly applies when referring to the amount of water to use.

Just like the ounces, gallons are not so easy to guess unless you know the formula. For that, you will need to convert the fluid ounces to the gallons.

How Many Ounces In A Gallon Of Ice Cream?

Okay, that's not the question I come across every day. But, whenever I have to buy ice cream for a group of people, especially during a potluck or feast, then I wonder how size should I buy?

When you think about the gallon unit, you need to understand that you can use it to measure other liquids besides water such as cream, milk, ice cream etc.

The truth is that whenever you think about serving ice cream, you tend to think about spoons. So, how many spoons will be in a gallon of ice cream.

Ice cream is not a liquid but a semi-solid mass. That means the measurement we use for a gallon of water is not the same for ice cream. In reality, a scoop of ice cream equals to 4 ounces of ice cream. That means a gallon of ice cream equals to 32 scoops. An average-sized ice cream scoop may vary from 4 to 6 ounces. If your ice cream scoop is of 6 ounces, then the gallon of ice cream will yield 21.3 scoops.

Whenever you are buying ice cream for a big, bunch of people, make sure to buy with an estimate that a gallon of ice cream may feed up to 30 people.

How many ounces in a gallon of milk?

A gallon equals to four quarts, and each unit equals to 32 oz or ounces. In that way, a gallon equals to 128 fluid ounces in total. Therefore, a gallon of milk - as sold in the super market - is equal to 128 ounces.


How many 32 oz. bottles make a gallon?

A gallon is 128 ounces, which means four 32 oz. bottles are equal to one gallon of water or any liquid.

How many 16 oz. bottles make a gallon?

Similarly, eight 16 oz. bottles make one gallon of water or any liquid.

How many 8 ounces’ glasses in a gallon?

The calculation is again the same, which means that 16 eight ounces glasses make a gallon.

How many 24 oz. bottles make a gallon?

As per the USA customary measurements, 5.3 24 oz. bottles make a gallon.

How many cups in a gallon?

Sixteen cups (liquid measurement cups) make a gallon of water. Click here to learn how many ounces in a cup.

How many ml in a gallon?

Milliliters or “ml” is another measurement in liquid volume. There are 3785.41 milliliters in one gallon of liquid.

How many liters in a gallon?

Similarly, there are 3.78541 liters in a gallon. Refer to the chart above for detailed information. If you are wondering how many ounces in a gallon of drinking water, then it's the same 128 ounces. Want to learn more about the benefits of drinking more water? Read here.

Click here to download the Kitchen Conversion Chart!

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Adrianne September 13, 2019 - 3:40 pm

Interesting! This is so helpful when cooking. thnka for the tops and information. Cheers

Raia Todd September 13, 2019 - 3:44 pm

Wow, that’s an awful lot of info! Haha. Thanks so much for having it all together in one place for us. 🙂

Sandhya Nadkarni September 13, 2019 - 3:58 pm

This is so helpful! I have bookmarked it!

Neli September 17, 2019 - 11:35 am

I must admit, I always wonder how many ounces are in a gallon. Love the comprehensive lists and the charts you have created, they help a lot! I will most likely come back to this post when I need to take a look at the conversion charts in the future.

Jess September 17, 2019 - 8:47 pm

Good to know and be reminded when doing all of this cooking! Thanks for sharing!

Michelle September 18, 2019 - 11:08 am

I love the liquid conversion visuals you have here. These are so very helpful for cooking! Wouldn’t it be nice if everyone just switched to the metric system?! Consistency and accuracy would be fabulous.

Veena Azmanov September 18, 2019 - 10:53 pm

Thanks for such amazing information. Really gives a lot of knowledge and help too.

Sharon September 21, 2019 - 8:29 am

This is going on my must-have for cooking essentials. So much knowledge in there!

Anne Lawton September 21, 2019 - 9:30 am

Thank you for all of this very useful information. Bookmarking this so I can refer back to it.

Eden September 22, 2019 - 11:53 am

Thank you for sharing this! Going to Pin to keep it on hand.

SHANIKA September 22, 2019 - 12:26 pm

This is such a helpful post! I couldn’t tell you how many times I’ve had to google measurements! Haha. Thanks so much for sharing!

Rebecca Blackwell September 22, 2019 - 1:14 pm

This post is now forever bookmarked on my computer so that I never ever have to figure out these conversions again. Who wants to do math while in the middle of a recipe??? Not this girl. 🙂 Thanks so much for doing all the work for us!

Eden | Sweet Tea and Thyme September 22, 2019 - 11:53 pm

Absolutely love your conversion chart! Every food blog needs one in my opinion.


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