1
Select the Tank Shape
Choose rectangular, cylindrical, spherical, or capsule based on the physical design of your tank.
Water Tank Volume Calculator
Calculate the total capacity, current water volume, remaining space, and estimated water weight for common tank shapes.
Tank Capacity Calculator
Choose a tank shape and enter its internal measurements.
Instant calculation
Your results will appear here
Enter the internal dimensions of your tank and select Calculate Tank Volume.
Total tank capacity
0 L
Rectangular tank
Current water volume
0 L
Remaining capacity
0 L
Estimated water weight
0 kg
20-liter containers
0
Tank fill level
100%
Liters
0 L
Cubic meters
0 m³
US gallons
0 gal
UK gallons
0 gal
Cubic feet
0 ft³
Simple process
How the Water Tank Volume Calculator Works
The calculator uses the standard geometric formula for your selected tank shape and automatically converts all measurements into compatible units.
2
Enter Internal Dimensions
Measure the inside length, width, height, or diameter. Select the correct unit beside each measurement.
3
Review the Capacity
Get total capacity, current water volume, remaining space, water weight, and conversions into common volume units.
Practical results
What This Calculator Provides
Total Tank Capacity
Find the maximum internal volume of a tank using its dimensions and geometric shape.
Current Water Quantity
Use the fill percentage control to estimate how much water is currently stored in the tank.
Water Weight Estimate
Estimate the weight of stored water. One liter of fresh water weighs approximately one kilogram.
About the Water Tank Volume Calculator
A water tank volume calculator helps homeowners, farmers, builders, plumbers, facility managers, and engineers estimate how much water a storage tank can hold. It is useful when selecting pumps, planning rainwater storage, estimating delivery requirements, or checking whether a tank is suitable for a property.
Accurate results depend on using the tank's internal measurements. External measurements can produce a slightly higher result because they include the thickness of the tank walls.
Rectangular Water Tank Formula
A rectangular or square tank requires its internal length, width, and height.
Volume = Length × Width × Height
Cylindrical Water Tank Formula
A cylindrical tank requires its internal diameter and length. The calculator first divides the diameter by two to determine the radius.
Volume = π × Radius² × Length
Spherical Water Tank Formula
A fully spherical tank requires only the internal diameter.
Volume = 4 ÷ 3 × π × Radius³
Capsule Tank Formula
A capsule tank consists of a cylindrical center with two hemispherical ends. The two hemispherical ends form one complete sphere.
Volume = Cylinder Volume + Sphere Volume
Common Water Volume Conversions
| Volume Unit | Equivalent Value |
|---|---|
| 1 cubic meter | 1,000 liters |
| 1 US gallon | 3.785411784 liters |
| 1 UK gallon | 4.54609 liters |
| 1 cubic foot | 28.316846592 liters |
Tips for More Accurate Results
Measure the usable internal space rather than the outside of the tank. Exclude thick walls, raised bases, internal supports, filters, and inaccessible sections. For irregular or heavily tapered tanks, use the manufacturer's official capacity instead of relying only on a standard geometric formula.
Common questions
Frequently Asked Questions
Multiply the internal length by the internal width and internal
height. Convert the resulting cubic measurement into liters,
gallons, or another preferred volume unit.
One cubic meter contains exactly 1,000 liters. A tank with an
internal volume of 2.5 cubic meters can therefore hold 2,500 liters.
Use internal measurements whenever possible. External measurements
include wall thickness and may overestimate the usable water capacity.
One liter of fresh water weighs approximately one kilogram under
normal conditions. Therefore, 1,000 liters of water weighs about
1,000 kilograms, excluding the tank's own weight.
Yes. You can enter each measurement in meters, centimeters,
millimeters, feet, or inches. The calculator automatically converts
them before applying the volume formula.
Yes. Use the current tank fill slider to enter the estimated
percentage of total capacity currently occupied by water.