Cylinder Volume Calculator
Enter any two of diameter, height, and volume — the third solves instantly.
Worked examples
Rainwater collection drum capacity
A homeowner wants to know how many liters a cylindrical rain barrel holds before ordering a matching lid and spigot kit.
- D
- 2 m
- H
- 3 m
≈ 9.4248 m³ (9,424.8 L)
Sizing a mixing vat from a target capacity
A fabricator needs a cylindrical mixing vat that holds exactly 5,000 L and stands 1.8 m tall — what diameter should they cut the shell to?
- V
- 5,000 L
- H
- 1.8 m
≈ 1.88 m diameter
How the formula works
A cylinder's volume is just the area of its circular cross-section multiplied by how far that circle extends — its height. The circle's area is π · r², where r is half the diameter, so stacking that constant cross-section up through height h gives the full formula below. Because there's only one equation with three quantities (D, H, V), knowing any two always pins down the third algebraically: solve the same equation for r (then double it for D) to get diameter from height and volume, or isolate h to get height from diameter and volume.
Frequently asked questions
How do I use the "Solve for" toggle?
Pick whichever of diameter, height, or volume you don’t know — that field locks and displays the answer, while the other two become the fields you fill in. There’s no separate "calculate" step: as soon as both remaining fields have valid numbers, the locked field updates live.
Does it matter which two values I enter?
No — the volume formula V = πr²h is symmetric in the sense that any two of the three quantities pin down the third, so diameter+height, diameter+volume, and height+volume all work equally well. The math is exactly the same algebra rearranged three different ways; pick whichever two numbers you actually have on hand.
Why is one field grayed out and not editable?
That’s the field currently being solved for, shown as a live result rather than an input so it’s never ambiguous which two numbers are driving the calculation. You can still switch its unit to view the answer in a different scale — use the "Solve for" toggle above to solve for a different field instead.
Is this the same as the tank volume calculator?
No — this tool assumes a plain, fully-full cylinder with no dished/domed heads and no partial fill level; it's a straightforward sizing calculator for pipe stock, tubing, cans, or any round container's total capacity. If you need a partial fill level, dished or hemispherical heads, a cone-bottom taper, or a horizontal orientation, use the Tank Volume Calculator instead — it shares this same core formula as one of its eight shapes.
What if I know a target volume and a diameter, and need the height?
Switch "Solve for" to Height, enter your diameter and target volume, and the required height calculates instantly. This is the common "how tall does this tube need to be" question when you’re sizing custom tubing, cores, or containers to hold a specific capacity.
Can I use this to size round bar or pipe stock?
Yes — the same π r² h relationship gives the volume of any solid cylindrical shape, so it works equally well for estimating material volume in round bar stock, shafts, or solid rod as it does for tank or tube capacity. For a hollow pipe's wall-material volume specifically, subtract the bore's volume (same formula, using the inside diameter) from the outside volume.