Based on the data available at Uniform Laws and Regulations in the areas of legal metrology and engine fuel quality adopted by the U.S. Department of Commerce and National Institute of Standards and Technology, the weight of 1 gallon of water is 8.3454020981 pounds, and it’s calculated at the temperature of 62 °F (17 °C).
What you should know about U.S. gallons and pounds
How much does a gallon of water weigh?
1 US gallon is exactly 8.3454020981 pounds at the temperature of 62 °F (17 °C).
Definition of US gallon of water provided by WikiPedia
the US gallon is defined as 231 cubic inches (3.785 l), which is used in the US and some Latin American and Caribbean countries
Definition of pounds of water provided by Merriam-Webster
any of various units of mass and weight; specifically : a unit now in general use among English-speaking peoples equal to 16 avoirdupois ounces or 7000 grains or 0.4536 kilogram
Weigh in pounds of common gallon values
At 62 °F (17 °C) a gallon of water weighs 8.3454020981 lb. Based on this, the following table contains various weighs in pounds for the most common gallon sizes. If you can’t find the gallon size you are looking for, use the converter above.
| Gallons of water | Pounds |
|---|---|
| 1 | 8.3454 |
| 2 | 16.6908 |
| 2.5 | 20.8635 |
| 3 | 25.0362 |
| 4 | 33.3816 |
| 5 | 41.727 |
| 6 | 50.0724 |
| 7 | 58.4178 |
| 8 | 66.7632 |
| 9 | 75.1086 |
| 10 | 83.454 |
| 20 | 166.908 |
| 30 | 250.3621 |
| 40 | 333.8161 |
| 50 | 417.2701 |
| 60 | 500.7241 |
| 70 | 584.1781 |
| 80 | 667.6322 |
| 90 | 751.0862 |
| 100 | 834.5402 |
| 200 | 1669.0804 |
| 300 | 2503.6206 |
| 400 | 3338.1608 |
| 500 | 4172.701 |
| 1000 | 8345.4021 |
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