Quick cubic feet water weight answers
For everyday planning, 1 cubic foot of fresh water weighs about 62.4 pounds and contains about 7.48 US gallons.
This is the common practical estimate for fresh water.
Use this when converting tank dimensions or pool dimensions into gallons.
Useful for larger tanks, shallow pool sections, and construction volumes.
At this size, structural load and drainage planning matter.
Cubic feet of water to pounds table
Use this table for fast cubic-foot water weight estimates.
| Cubic feet | US gallons | Approx. pounds | Approx. kilograms | US tons |
|---|---|---|---|---|
| 1 ft³ | 7.48 gal | 62.4 lb | 28.3 kg | 0.03 tons |
| 2 ft³ | 15.0 gal | 124.8 lb | 56.6 kg | 0.06 tons |
| 5 ft³ | 37.4 gal | 312 lb | 141.5 kg | 0.16 tons |
| 10 ft³ | 74.8 gal | 624 lb | 283 kg | 0.31 tons |
| 25 ft³ | 187 gal | 1,560 lb | 708 kg | 0.78 tons |
| 50 ft³ | 374 gal | 3,120 lb | 1,415 kg | 1.56 tons |
| 100 ft³ | 748 gal | 6,240 lb | 2,830 kg | 3.12 tons |
| 250 ft³ | 1,870 gal | 15,600 lb | 7,076 kg | 7.80 tons |
| 500 ft³ | 3,740 gal | 31,200 lb | 14,152 kg | 15.60 tons |
| 1,000 ft³ | 7,481 gal | 62,400 lb | 28,304 kg | 31.20 tons |
When cubic feet are useful
Cubic feet are common when the water volume comes from dimensions instead of a labeled container size. For example, a rectangular tank, pit, pool section, flood depth, or water-filled box can be measured in length × width × depth, then converted into water weight.
Tanks and containers
If a tank is measured in feet, multiply length × width × water depth to estimate cubic feet. Then use this calculator to convert that volume into pounds, kilograms, and gallons. For tank shell, trailer, frame, and accessory load, use the Water Tank Weight Calculator.
Pools and large water volumes
For pool planning, cubic feet can be converted to gallons and pounds. If you need shape-based pool volume, average depth, and tons of water, use the Swimming Pool Water Weight Calculator.
Aquariums and indoor loads
Aquariums are often measured in inches, centimeters, gallons, or liters, but the same water-weight rule applies. For fish tank dimensions and optional total load, use the Aquarium Water Weight Calculator.
Formula for cubic feet of water weight
1 cubic foot of water ≈ 62.4 pounds
1 cubic foot ≈ 7.48052 US gallons
pounds ≈ cubic feet × 62.4
kilograms ≈ pounds × 0.453592
This calculator uses fresh water as the default. Saltwater is slightly denser, so the same cubic-foot volume weighs slightly more.
More water weight calculators
Cubic feet water weight FAQ
How much does a cubic foot of water weigh?
One cubic foot of fresh water weighs about 62.4 pounds, or about 28.3 kilograms, for everyday planning.
How many gallons are in a cubic foot of water?
One cubic foot contains about 7.48 US gallons of water.
How do I calculate water weight from dimensions?
For a rectangular volume measured in feet, multiply length × width × water depth to get cubic feet. Then multiply cubic feet by about 62.4 to estimate pounds of fresh water.
Is cubic feet better than gallons?
Use cubic feet when you have dimensions. Use gallons when the container capacity is already labeled in gallons. Both can be converted to water weight.
Can I use this for structural load?
Use it only as a planning estimate. For decks, buildings, slabs, trailers, heavy tanks, or unusual loads, consult a qualified professional.