Water Tank Calculator
Calculate the liquid holding capacity of cylindrical or rectangular water storage tanks in cubic feet, gallons, and liters.
Calculation Results
Total holding volume of the tank in cubic feet.
Total liquid holding capacity of the tank in US gallons.
Total liquid holding capacity of the tank in liters.
How This Calculator Works
To calculate tank volume and liquid capacity:
- Select the tank shape (Cylindrical or Rectangular).
- Provide the requested dimensions (diameter and height, or length, width, and height).
- The calculator determines total capacity in cubic feet, gallons, and liters.
Formula & Calculations
Water tank volume formulas depend on the selected shape:
- Cylindrical Tanks:
Volume = π × (Diameter / 2)² × Height - Rectangular Tanks:
Volume = Length × Width × Height
Unit conversions scale from the base unit (cubic feet) to liquid volume:
- US Gallons: Multiply cubic feet by
7.4805. - Liters: Multiply cubic feet by
28.3168.
Step-by-Step Calculation Examples
Typical Cylindrical Water Cistern (6ft diameter, 8ft height)
Calculating the water volume capacity of a standard vertical round cistern.
- tank_type: cylinder
- diameter: 6
- height: 8
- volume_cu_ft: 226.19 cu ft
- volume_gallons: 1692.0 gal
- volume_liters: 6405.1 L
Frequently Asked Questions
How do I calculate the capacity of a round water tank?
Measure the inside diameter and the water depth height. The volume is calculated as: Volume = π × (diameter / 2)² × height. Multiplying this cubic feet volume by 7.48 gives the total gallons.
How many gallons of water are in a cubic foot?
There are approximately 7.48052 US liquid gallons in one cubic foot of water.
How much does a water tank weigh when full?
Water weighs exactly 8.34 pounds (3.785 kg) per gallon, or 62.4 pounds per cubic foot. A 1,000-gallon water tank will weigh approximately 8,340 pounds (over 4 tons) of water weight alone.
Should I calculate volume based on the tank size or water level?
If you want to know the maximum capacity, measure to the overflow drain. If you want to know current inventory, measure only to the height of the actual water surface.
How many liters of water are in a gallon?
One US liquid gallon is equivalent to exactly 3.78541 liters of water.