Calculate water volume, length, width, or depth from any three values with unit conversions for feet, meters, inches, centimeters, and gallons.
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Water Volume Formula
The calculator uses the rectangular volume formula. It converts all length measurements to feet, calculates in cubic feet, then converts the result to the volume unit you selected.
- V = water volume
- L = water length
- W = water width
- D = water depth
If you leave the volume field blank, the calculator multiplies length, width, and depth to find the water volume. If you leave length, width, or depth blank, it rearranges the same formula to solve for the missing dimension.
The internal base units are feet for length and cubic feet for volume. Results can be shown in US gallons, liters, cubic feet, or cubic meters.
Water Volume Unit Conversions
These are the main conversion values used when switching between measurement units.
| Measurement | Equivalent |
|---|---|
| 1 cubic foot | 7.48052 US gallons |
| 1 cubic foot | 28.3168 liters |
| 1 cubic meter | 35.3147 cubic feet |
| 1 meter | 3.28084 feet |
| 1 inch | 0.0833333 feet |
Common Rectangular Water Volumes
| Length | Width | Depth | Volume | Approx. US Gallons |
|---|---|---|---|---|
| 4 ft | 3 ft | 2 ft | 24 cu ft | 179.53 gal |
| 8 ft | 4 ft | 2 ft | 64 cu ft | 478.75 gal |
| 10 ft | 5 ft | 3 ft | 150 cu ft | 1,122.08 gal |
Example Problems
Example 1: Find water volume in gallons
You have a rectangular space of water that is 10 ft long, 5 ft wide, and 3 ft deep.
The water volume is about 1,122.08 US gallons.
Example 2: Find missing depth
You have 478.75 gallons of water in a rectangular area that is 8 ft long and 4 ft wide.
The water depth is about 2 ft.
FAQ
Can this calculator be used for pools, tanks, and containers?
Yes, if the water area is rectangular or can be reasonably treated as a rectangular box. Enter the inside length, inside width, and water depth. For round, oval, sloped, or irregular shapes, this formula will only give an estimate.
Why does the calculator ask for exactly 3 values?
The formula has 4 variables: length, width, depth, and volume. If you provide any 3 of them, the missing value can be calculated. If more than one field is blank, there is not enough information to solve the problem.
Should I use total container depth or current water depth?
Use the current water depth if you want the actual amount of water present. Use the full inside depth only if the container is filled to the top.
