What is the weight of 1 gallon of water?

In this brief guide, we will answer the query, “What is the weight of 1 gallon of water?”. We will also compare the weight of milk and 1 gallon of water and we will discuss how much water you should drink in a day.

What is the weight of 1 gallon of water?

A gallon of water is 3.785 liters in the US which weigh 3.785 kilograms or 8.33 lbs. In the UK the gallons measure 160 fluid ounces which are 4.546 liters.  The water is a dense liquid as the water molecules are packed densely.

1 cm³  of water is 1 ml and weighs 1 gram which accounts for 1 liter of water weighing 1 kilogram. As 1 gallon of water is 3.785 liters in the US, it weighs 3.785 kilograms. As for the UK measuring standards, 1 gallon of water weighs 4.546 kilograms.

Do other factors affect the weight of water? 

Environmental factors can change the weight of water per gallon such as temperature. The change in temperature affects the behavior and the weight of water.

Heating a gallon of water can decrease the density of water as the molecules will start to move rapidly and create more room around them as they are densely packed at room temperatures. As the density decreases, the weight decreases as well.

A gallon of cold water is heavier compared to a gallon of hot water as the density of cold water is higher as the water molecules are tightly packed which allows more water to be filled in the gallon.

Does a gallon of water weigh the same as a gallon of milk?

No, a gallon of water weighs less than a gallon of milk as milk constitutes about 87% water with other substances such as fat and milk solids which are heavier than water. A gallon of milk is heavier than a gallon of water.

How much water should you drink in a day?

The US National Academies of Sciences, Engineering, and Medicine recommends 11.5 cups or 2.7 liters a day of water for women and 15.5 cups or 3.7 liters a day of water for men. The water intake just does not mean gulping on bottles of water, it is also from the fruits and vegetables and other beverages such as tea, coffees, sodas, and juices.

Even though coffee and tea contain caffeine which has diuretic properties, it still helps to hydrate the body slightly. If you are following a properly balanced diet, you can average 20% of your water intake from the food you consume. 

It is really necessary and vital for the person to stay hydrated as the body loses a significant amount of water through sweat and urine. The body dehydrates through breathing and other bodily functions on a daily basis. 

The human body is 60% water and it is necessary to replenish the lost water content to keep the body functioning properly. It is advised to at least drink 2 liters of water daily to keep up with the dehydration.

Can drinking water prevent certain health issues? 

Drinking an adequate amount of water is necessary for the functioning of the body. Dehydration can cause many health disorders which can be countered by drinking enough water to stay hydrated.


Drinking enough water daily can reduce or even relieve constipation. Constipation is caused due to the low water content in the stool in the intestine. Adequate intake of water can help the stool to be soft, hence relieving constipation.

Urinary tract infections 

The urinary tract infections can also be healed by drinking enough water which helps the tract and the kidneys to function well. The urinary bladders are also prone to infections which can be treated by drinking enough water to flush the urinary system including the bladders.

Kidney stone 

Drinking lots of water can make the stones in the kidney pass out through urine. It is also said that drinking water can decrease the risk of kidney stones too.

Skin hydration

Drinking enough water not only hydrates the internal bodily systems but also helps hydrate the skin which avoids the risks of skin-related diseases caused due to drying of skin such as acne.


In this brief guide, we answered the query, “What is the weight of 1 gallon of water?”. We also compared the weight of 1 gallon of milk and 1 gallon of water and we discussed how much water you should drink in a day.

I hope you find this blog useful. If you have any questions, please let us know.




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