What is a Tank Volume Calculator?
A tank volume calculator computes the liquid or material capacity of a tank based on its shape and dimensions. Tanks are used throughout construction for water storage, fuel storage, septic systems, chemical holding, and fire suppression systems. Accurate volume calculation is essential for sizing tanks, estimating fill quantities, and ensuring compliance with building and environmental codes.
The most common tank shapes are vertical cylinders, horizontal cylinders, and rectangular tanks. Each requires a different formula based on its geometry. This calculator handles all three shapes and converts between gallons, liters, cubic feet, and cubic meters.
Tank Volume Formulas
Volume Conversions
| Unit | Gallons | Liters | Cubic Feet |
|---|---|---|---|
| 1 Gallon | 1 | 3.785 | 0.1337 |
| 1 Liter | 0.2642 | 1 | 0.0353 |
| 1 Cubic Foot | 7.481 | 28.32 | 1 |
| 1 Cubic Meter | 264.2 | 1,000 | 35.31 |
Worked Example
A vertical cylindrical tank 4 ft diameter by 6 ft tall:
= 564 gallons = 2,134 liters
Frequently Asked Questions
How many gallons in a cubic foot?
One cubic foot equals 7.4805 US gallons. To convert tank volume in cubic feet to gallons, multiply by 7.4805.
How do I calculate a partially filled horizontal tank?
For a horizontal cylinder partially filled, the volume depends on the fill depth and requires a more complex calculation involving the circular segment area multiplied by the tank length. This calculator provides full capacity only.
What size tank do I need for my home?
A typical residential water storage tank is 500–2,500 gallons. Septic tanks range from 750–1,500 gallons depending on household size. Consult local codes for minimum sizing requirements.