How Much Does A Gallon Of Water Weigh? Easy Explanation

If you have landed over this page then definitely you must be looking for how much does a gallon of water weigh?

Well to be very precise a weight of a gallon of water is around 8.3 pounds which is almost equal to 3.7 Kg.

how much does a gallon of water weigh
how much does a gallon of water weigh

How Much Does A Gallon Of Water Weigh

A Gallon

Gallon is the unit of measurement which is used to determine the capacity of solid, gases and liquids.

Using Galon, we can easily measure the capacity of liquids in both US customary units and the British imperial system.

There are three different sizes of gallons that we use today, the first one is an imperial gallon that is used in Canada, the UK and some other Caribbean countries.

The second one is the US gallon which is mainly used in the US and some Latin American countries.

The third one is US dry gallon which is the least used among all of the three.

An imperial gallon is defined as 4.546 Liters, Us gallon as 3.78 Liters and US dry gallon as 4.405 liters.

Now, the question is how much does one gallon of water weigh?

The answer is simple, a gallon of water weighs about 8.3 pounds.

The imperial gallon of water is defined as 10.02 pounds at its maximum density while the weight of the US dry gallon of water is defined as 9.71 pounds. 

Note: The weight per gallon of water fluctuates with respect to temperature

Effect Of Temperature On Water Weight

One of the ways to measure the amount of energy in water is Temperature.

Water having a higher temperature means higher energy and vice versa.

If we increase the temperature of water then its molecules start vibrating and pushing their neighbors to the side.

This shows that with the increase in the energy of water its density decreases.

And as we know that gallon is a fixed amount of space, the number of molecules in that space starts fluctuating with the increase in temperature.

So, a gallon of warm water is slightly lighter than that of cold water due to the difference in the temperature.

Let’s take an example, the weight of a gallon of water would be 8.3 pounds at 500 Fahrenheit while it will 8.03 pounds at 2000 Fahrenheit.

Keep in mind that the value of water will be the same because the temperature does not affect water composition.

Effect Of Pressure And Gravity On Weight Of Water Per Gallon

Weight of water per gallon can also be affected by atmospheric pressure and gravity.

Gravitational pull increases the weight of water, for example, the weight of one gallon of water will be less on the moon as compared to the Earth.

But will weight more on Jupiter compared to Earth.

The Earth has a high gravity that provides high gravitation force compared to moon.

That’s the reason why a gallon of water weight more on earth than on the moon.

Although, the value of the water does not change with a change in gravitational pull.

How Much Does Water Weigh

The weight of a volume of water can be found given the density, which is the mass compared to the volume.

The density of water is 1 kilogram per liter (kg/L) at 39.2°.

1 Liter (L) Of Water = 1 Kilogram (Kg)

1 Milliliter (ml) Of Water = 1 gram (g)

1 gallon of water = 3.7 Kilogram (Kg)


1. How much does a gallon of milk weigh?

A gallon of milk weighs around 8.6 pounds (lb)

2. How much does 5 gallon of water weigh?

5 gallon of water weight around 41.7 pounds (lb) / 18.9 Kilogram (Kg)

3. How much does a liter of water weigh?

A liter of water weighs 1 Kilogram (Kg)

4. How many pounds are in a gallon?

1 US gallon (gal) = 8.35 pounds (lb)


This article is all about how much does a gallon of water weigh and I have answered almost all queries related to this topic.

Go through the entire article if you are unable to understand it in one time.

If you have any doubt drop your comments below, I’ll be happy to help you guys.

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