Guides
Calculating Hexagon and Corner Tank Volume
Odd-shaped aquariums are tricky to measure. Here is how to calculate the volume of hexagon and corner fish tanks accurately.
Read more →Cylinder & Round Fish Tank Volume Calculator
Volume
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Enter your tank dimensions to see the volume.
Did we solve your problem?
Calculate the volume of a cylindrical or round aquarium. Enter the diameter and height and get the capacity in litres and gallons.
How cylinder tank volume works
A round tank is a cylinder, so its volume is pi times the radius squared times the height, where the radius is half the diameter. The calculator computes this automatically.
Example sizes and volumes
| Diameter (cm) | Height (cm) | Litres | US gallons |
|---|---|---|---|
| 30 | 50 | 35.3 | 9.3 |
| 40 | 60 | 75.4 | 19.9 |
| 50 | 60 | 117.8 | 31.1 |
| 60 | 80 | 226.2 | 59.8 |
| 80 | 100 | 502.7 | 132.8 |
| 100 | 120 | 942.5 | 249 |
Calculated with the same formula as the calculator above. Values are rounded.
Shape preview
Adjust the size and height to see this tank shape and its volume.
Volume ≈ — litres
Formula
V = π × (diameter / 2)² × height Related calculators
Frequently asked questions
How do I calculate cylinder fish tank volume?
Enter the diameter and height. The formula is pi times the radius squared times the height, with the radius being half the diameter.
What is the radius of a round tank?
It is half the diameter, measured from the centre of the circular base to the edge.
How do I calculate a half or quarter cylinder?
Choose the half cylinder or quarter cylinder shape, which divide the full cylinder volume by two or four.
Are round tanks good for fish?
Tall, narrow cylinders limit swimming space and surface area, so a wider cylinder is a healthier choice.
What units can I use in this calculator?
You can switch between centimetres, millimetres, inches, feet and metres at any time. Enter all dimensions in the same unit and the result updates instantly.
Does the result include substrate and decoration?
The figure is the full internal capacity. Subtract roughly 10 to 15 percent for substrate, rocks and the gap you leave at the top to estimate the real water volume.
How accurate is this fish tank calculator?
It uses the exact geometric formula for each shape, so the result is accurate for the dimensions you enter. Measure the inside of the tank for the best accuracy.
Is this calculator free to use?
Yes. It is completely free, needs no sign-up, and works on phones, tablets and desktops.
Related guides
Learn the core ideas behind fish tank volume before or after using the calculator.
Guides
How to Find the Volume of a Fish Tank
How to measure a fish tank properly and find its volume in litres and gallons, with formulas for rectangular, cylinder, hexagon and corner tanks.
Read more →Conversions
How Many Gallons Is My Fish Tank? Calculate Aquarium Gallons
Measure your tank and divide by 231 for US gallons. Worked examples, US vs UK gallons, and how to identify an unknown tank by its footprint.
Read more →