Water Weight Calculator
Calculate the weight of water by volume in gallons, liters, cubic feet, or cubic meters. Quick reference table included.
WATER WEIGHT
8.35 lbs
IN kg
3.79 kg
LITERS
3.79
GALLONS
1
Water Weight β Quick Reference
| Volume | Weight (lbs) | Weight (kg) |
|---|---|---|
| 1 cup (8 oz) | 0.5 | 0.2 |
| 1 quart | 2.1 | 0.9 |
| 1 gallon | 8.3 | 3.8 |
| 5 gallons | 41.7 | 18.9 |
| 1 cubic foot | 62.4 | 28.3 |
| 55 gal drum | 459 | 208.2 |
| Hot tub (400 gal) | 3,338.2 | 1,514.2 |
| Pool (20k gal) | 166,907.4 | 75,708 |
π‘ How Much Does Water Weigh?
Weight of Water by Volume
Water at room temperature (approximately 4Β°C for maximum density) weighs exactly 1 kilogram per liter, or about 8.34 pounds per US gallon. This makes water a convenient reference standard for density measurements.
Water Weight Reference
1 liter = 2.205 lbs (1.000 kg)
1 cubic foot = 62.43 lbs (28.32 kg)
1 cubic meter = 2,205 lbs (1,000 kg = 1 metric ton)
Practical Applications
Knowing the weight of water is important for aquarium setup (a 55-gallon aquarium weighs about 459 lbs when full), pool filling (a 20,000-gallon pool weighs about 167,000 lbs = 83.5 tons), plumbing design, water trucking (weight limits), and emergency water storage planning.
A standard 55-gallon drum of water weighs 459 lbs. A standard bathtub filled to capacity (~50 gallons) weighs about 417 lbs. A hot tub (400 gallons) weighs over 3,300 lbs β which is why they require structural support and a reinforced deck or pad.