How tank capacity is calculated
A cylindrical tank's volume is the area of its circular cross-section times its height. Converting that volume from cubic centimeters gives the capacity in liters and cubic meters.
- diameter — tank diameter (cm)
- height — tank height (cm)
- V — volume in cubic centimeters (cm³)
Common values
| Diameter (cm) | Capacity |
|---|---|
| 10 cm | 11.8 L |
| 25 cm | 73.6 L |
| 50 cm | 294.5 L |
| 100 cm | 1,178.1 L |
| 150 cm | 2,650.7 L |
| 200 cm | 4,712.4 L |
| 300 cm | 10,602.9 L |
| 500 cm | 29,452.4 L |
| 1,000 cm | 117,809.7 L |
More detail
Why diameter, not radius
Tank specs and tape measurements almost always give the diameter (the full width you can measure across the top), so this calculator takes diameter directly and halves it internally — no manual conversion needed.
Liters vs. cubic meters
1 liter equals 1,000 cm³, and 1 cubic meter equals 1,000 liters. Liters are the practical unit for water usage and delivery; cubic meters are what utility bills and larger tank specs usually quote.
Measuring tip. Measure the inside diameter and the inside height (or the water depth you actually want to fill) for the most accurate usable capacity — outer dimensions overstate it once wall thickness is factored in.
Frequently asked questions
What is the capacity of a tank with 100cm diameter and 150cm height?
Volume = π × (100÷2)² × 150 = π × 2,500 × 150 ≈ 1,178,097 cm³, which is about 1,178.1 liters or 1.178 m³. Enter your own diameter and height above to get exact figures.
How do I convert tank volume from liters to cubic meters?
Divide liters by 1,000 — 1 m³ equals exactly 1,000 liters, since a cubic meter is 100cm × 100cm × 100cm = 1,000,000 cm³ and 1 liter is 1,000 cm³. Both outputs above are calculated directly from the same volume in cm³.
Does this work for a rectangular tank?
No — this calculator assumes a cylindrical (round) tank using V = π × r² × height. A rectangular or square tank uses V = length × width × height instead, with no π term.
Why might my actual tank hold less than the calculated volume?
The formula assumes a perfect cylinder measured to the inside wall. Domed or sloped tank bottoms, wall thickness, and internal fittings (pipes, floats) all reduce usable capacity below the ideal geometric volume — treat the result as an estimate.
What if I only know the radius, not the diameter?
Multiply the radius by 2 to get the diameter before entering it above — this calculator's formula halves the diameter internally to recover the radius, so entering the radius directly would give a result 4 times too small.