Large Tank Volume — 12 ft Diameter, 20 ft Tall
A 12 ft diameter, 20 ft tall cylindrical tank can hold approximately 16,965 US gallons.
How to use this tool
- Enter the tank's inside diameter and height in feet.
- The calculator returns volume in cubic feet, US gallons, and litres.
- For rectangular tanks, use length × width × height in ft³ and multiply by 7.48 for gallons.
Estimate the large-volume storage capacity of a commercial or municipal cylindrical water tank.
Frequently asked questions
- How do I calculate water tank volume?
- For a cylindrical tank, use: Volume = π × (diameter/2)² × height. Multiply cubic feet by 7.48 for US gallons or by 28.32 for litres.
- How many gallons is a cubic foot?
- One cubic foot of water holds approximately 7.48 US gallons or 28.32 litres.