Cylindrical Tank Calculator
Calculate tank volume, height, diameter, or liquid weight for water tanks, fuel tanks, and cylindrical containers. Free, instant, runs in your browser.
Calculate Volume
Enter radius and height to calculate the volume of a cylindrical tank in liters or cubic meters.
Calculate Height
Enter radius and volume to calculate the required height of a cylindrical tank.
Calculate Weight
Enter volume and material density to calculate the weight of liquid in a cylindrical tank.
Calculate Diameter
Enter volume and height to calculate the diameter and radius of a cylindrical tank.
How to use the cylindrical tank calculators
Four calculators for every cylindrical tank dimension: volume, height, diameter, and weight.
- 01
Choose a calculator
Select Volume to calculate capacity, Height to find the required height for a given volume, Weight to calculate liquid weight, or Diameter to find the tank diameter.
- 02
Enter the known dimensions
Fill in the dimensions you know. The tool calculates the unknown value instantly.
- 03
Choose your units
Lengths can be in mm, cm, m, km, inches, feet or yards. Volumes come out in litres and cubic metres, and weights in kilograms, tonnes and pounds.
What people use it for
Water tank sizing
Calculate the volume of a cylindrical water tank to determine how many liters it holds.
Fuel tank capacity
Find the capacity of a cylindrical fuel tank given its diameter and height.
Industrial tanks
Calculate dimensions for storage tanks, chemical vessels, and industrial containers.
Plumbing and piping
Calculate the volume of water in cylindrical pipes for flow rate and pressure calculations.
Construction planning
Calculate the volume of cylindrical columns, pillars, or concrete forms.
Liquid weight estimation
Calculate how much a full tank weighs to check structural load requirements.
Worked example and the limits of a perfect cylinder
Volume is π × r² × h. A vertical tank 1.2 m across and 1.5 m tall has a radius of 0.6 m, so its volume is π × 0.36 × 1.5 = 1.696 m³, or 1,696 litres. Full of water (1 kg per litre) it weighs about 1,696 kg plus the tank, which matters if it's going on a roof.
Other liquids weigh less. Diesel is roughly 0.83–0.85 kg per litre, so the same tank of diesel weighs around 1,420 kg. Use the weight calculator with the right density for your contents.
The calculators assume a straight-sided cylinder. Tanks with domed or conical ends hold a little more, and the 1,000 L or 2,000 L printed on plastic water tanks is a nominal size. A horizontal tank that's partly full doesn't fill linearly either, so a dipstick reading at half the diameter isn't half the volume except at exactly the middle.
Which cylinder calculator to use
All four share the same geometry, V = π × r² × h, and each solves for a different unknown:
| You know | You want | Use |
|---|---|---|
| Diameter and height | How much it holds | Volume calculator |
| Volume and diameter | How tall it must be | Height calculator |
| Volume and height | How wide it must be | Diameter calculator |
| Size and what's inside | How heavy it is when full | Weight calculator |
A quick sense of scale helps when checking results: a tank 1 m across and 1 m tall holds about 785 litres, and every extra 10 cm of height on that tank adds about 78.5 litres. Doubling the diameter quadruples the volume, while doubling the height only doubles it.
Measuring a real tank
- Measure the inside diameter where you can, or subtract twice the wall thickness from the outside measurement.
- For the usable volume, use the height up to the overflow or outlet, not the full tank height.
- Round tanks with domed or cone bottoms hold a little more or less than a straight cylinder; the calculators assume flat ends.
- For horizontal tanks the full volume is the same, but part-full volumes need a different formula that these tools don't cover.