How Much Does Milk Weigh? | Type Matters


How much milk are you actually getting when you buy a gallon of milk? Is a gallon of whole milk heavier than a gallon of skim or 2% milk? These may seem like odd questions, but many people are interested in finding out the answers.

A gallon of milk weighs about 8.6 pounds (3.9 kg). However, it depends on different factors, such as the type of milk you’re buying (whole, skim, etc.), the size (gallon, liter, etc.), the material used to make the container (glass, plastic, etc.), and the temperature.

This article will break down the different weights of milk using the type of milk, the size of the container, and other factors. If you’ve ever wanted to know anything about the weight of milk, you’ve come to the right place. 

Figuring Out the Weight of Milk

According to the USDA, a gallon of whole milk weighs approximately 8.6 pounds (3.9 kg). 

After conducting a few hands-on experiments with a dairy farmer I know, we found that to be accurate. Our measurements were slightly different, but the differences were so slight as to be negligible. 

If you don’t have a dairy farmer nearby who’s willing to experiment with you, there are a few other ways you can determine the weight of milk.

Weigh It

The easiest way to figure out the weight of milk is to weigh it. 

Start by weighing an empty container and recording its weight. Then pour the gallon of milk into the container and weigh it again. Finally, subtract the weight of the container from the total weight of the container when it’s full of milk, and you’ll have your answer. 

Use Science/Engineering Formulas

However, using science and math, you can also calculate the weight of milk without ever touching a gallon of the stuff. 

Engineering Clicks explains how that works, but it also urges you to be careful using the density of milk to calculate weight because density can change depending on the temperature. 

Nevertheless, assuming the temperature is such that the density of milk is approximately 1.033 kg per liter (2.277 pounds per liter), the formula breakdown looks something like this:

  • The density of milk is 1.033 kg/liter (2.277 lbs/liter)
  • One US gallon is equal to 3.785 liters (7.999 pt)
  • The 1.033 kg (2.277 lbs) density multiplied by 3.785 liters (7.999 pt) = 3.909 total kg
  • 3.909 total kg converted to pounds = 8.617 pounds

Even when done with math instead of pails and scales, the answer is almost exactly the same.

However, because density can change with temperature fluctuations, weighing the milk is the easiest, most effective way to get an accurate weight determination.

How Much Does a Gallon of Milk Weigh in Ounces?

Milk-Being-Poured-into-a-Glass

To figure this out, you have the same two options. 

You can physically weigh the milk using a scale, or you can use several math formulas to determine the weight of milk in ounces. Since we already know a gallon of whole milk weighs 8.6 pounds (3.9 kg), I’m going to go with math this time. 

Simple conversion tells us that there are 16 ounces in a single pound. Therefore, if one gallon of whole milk weighs 8.6 pounds (3.9 kg), all we have to do is multiply that number by 16. 

  • 8.6 pounds x 16 (ounces per pound) = 137.6 ounces

A gallon of whole milk weighs 137.6 ounces (3,900.9 grams). Once you’ve determined the weight of any other type of milk, which we’ll do down below, you can multiply that number by 16 and figure out how much each kind of milk weighs in ounces.

Does Milk Weigh More Than Water?

Most people correctly assume that milk is heavier than water, but not everyone knows exactly why that is the case. Does milk weigh more than water or does water weigh more than milk? Let’s find out!

Milk weighs more than water because water is simply water. Milk, on the other hand, is comprised of many things, including fats, proteins, carbohydrates, vitamins, minerals, and several different solids. These all add more mass to the milk, making it denser and heavier than pure water.

How Much Does a Gallon of Whole Milk Weigh?

The weight of a gallon of whole milk will be slightly different depending on what kind of container is holding it. Whole milk might be heavier, because of the fats, right? It turns out that fats don’t contribute to how much milk weighs.

Assuming it’s in a “regular” plastic container, a gallon of whole milk weighs approximately 8.6 pounds (3.9 kg). The milk itself weighs almost that much on its own, and any additional weight from the plastic container is almost too minuscule to count since it’s no more than a couple of ounces.

How Much Does a Gallon of 2% Milk Weigh?

The type of milk (whole milk, skim milk, 2% milk, etc.) doesn’t make a significant difference in how much it weighs, but there are slight variations between types. Is it due to fat or water?

A gallon of 2% milk weighs almost the same as whole milk, which is about 8.6 pounds (3.9 kg) as long as they’re packaged in plastic. A gallon of 2% milk may be slightly lighter at around 8.5 pounds (3.85 kg), but depending on the temperature and density, you may not measure any difference at all. 

How Much Does a Gallon of 1% Milk Weigh?

Assuming they’re packaged in the same type of container, there isn’t much difference in weight between 1% and 2% milk.

Usually, 1% milk and 2% milk weigh almost exactly the same, between 8.5 and 8.6 pounds (3.86 kg – 3.9 kg). As with all the other types of milk, the current temperature will affect the density of 1% milk, and as the milk’s density changes, the weight of the milk will fluctuate very slightly.

How Much Does a Gallon of Skim Milk Weigh?

Ironically, skim milk is a tiny bit heavier than whole milk because the liquid used to replace the extracted fats is heavier than the fats themselves. Who would have thought that water would weigh more than fat?

Once the fat is removed and replaced with liquid, skim milk weighs about 8.62 pounds (3.91 kg). According to the popular engineering website, Engineering Clicks, skim milk weighs slightly more than whole milk because fat weighs less than water, which is why “the cream always rises.” 

What Does 1 Liter of Milk Weigh?

In terms of liters, the weight of milk is significantly lower than a gallon of milk, only because, by volume, a liter of milk is less than a gallon of milk.

Because the density of milk is close to one kilogram (2.2 lbs), the weight of a liter of milk is also close to one kilogram (2.2 lbs). The exact weight is 1.033 kg (2.27 lbs) for most varieties, but that can fluctuate depending on the current temperature and the type of container holding the milk.

What Does a Quart of Milk Weigh?

When it comes to the weight of a quart of milk, both the USDA and Reference.com have us covered. Of course, a gallon of milk will weigh more than a quart of milk, due to the reasons given above.

According to the USDA, a quart of milk weighs approximately 2.15 pounds (975 g), which includes both quarts of milk packaged in cardboard or plastic containers. Quarts of milk in glass containers will weigh more due strictly to the added weight of the glass. 

What Does One Pint of Milk Weigh?

The easiest way to figure out how much a pint of milk weighs is to use simple conversion methods, such as those talked about earlier in this article. Let’s take a look at how much a pint of milk weighs.

Because we know that there are two pints in a single quart and that a quart of milk weighs approximately 2.15 pounds (975 g), we can easily determine that one pint should weigh about half of that, which comes out to about 1.075 pounds (487.61 g).

How Much Does a Half Gallon of Milk Weigh in Pounds?

As is true for a gallon of milk, finding out the weight of a half-gallon of milk depends on a few different factors. 

Assuming most milk weighs close to 8.6 pounds (3.9 kg) per gallon, you can divide that in half to determine how much a half-gallon would weigh, which gives you 4.3 pounds (1.95 kg). The precise weight of a half-gallon of milk depends on whether it’s whole, skim, or something else. 

Final Thoughts

While knowing how much milk weighs may not be something about which everyone is curious, it’s still an interesting fact. Plus, you never know when you might need to know some random bit of trivia to win a million dollars on a game show! 

Although measurements are slightly different depending on the current temperature and the specific type of milk you’re buying, it’s generally accepted that a gallon of milk weighs around 8.6 pounds (3.9 kg).

Thanks for stoppin’ by! For more, check out 15 Best Substitutes for Milk in Mac and Cheese.

Anne James

Hi, I'm Anne but my grandchildren call me Jelly Grandma. I have over 50 years of experience as a Southern cook and am a retired librarian. I love sharing what I have learned. You can find me on YouTube as well! Just click the link at the bottom of your page. I hope your visit here has been a sweet one.

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