What this calculator does
Cylinder volume is normally taught with the formula V = πr²h, which needs a radius. Measuring a pipe, tube or tank with a tape measure or calipers, though, usually gives a diameter, and this diameter of a cylinder calculator takes that measurement straight in, working out the volume of a cylinder with diameter without an extra manual step.
The maths underneath is the same either way, since the diameter is simply divided by two internally before the standard formula runs. What changes is convenience: entering the number actually on the tape measure or spec sheet, rather than doing the halving in your head or on a separate calculator first.
The formula
The radius used internally is half the entered diameter. Volume is then π times that radius squared times the height, and total surface area adds the two circular end caps to the curved side, expressed directly in terms of diameter and height.
| Term | Meaning |
|---|---|
| d | The diameter of the cylinder, the full width across its circular face. |
| h | The height (or length, for a horizontal cylinder) of the cylinder. |
| V | Volume: π(d/2)²h. |
The inputs explained
| Field | What to enter |
|---|---|
| Diameter | The diameter of the cylinder, measured straight across the circular face. |
| Height | The height of the cylinder, measured along its axis. |
When to use it
Sizing a pipe or tube from a spec sheet
Pipe specifications are almost always given as a diameter (nominal or actual), so entering that figure directly avoids halving it before working out how much the pipe can hold.
Estimating tank capacity from an outside measurement
Wrapping a tape measure around a cylindrical tank and dividing by π gives a diameter more naturally than a radius, since there is no centre point to measure from on the outside.
Cross-checking a radius-based calculation
Doubling a known radius and running it back through this calculator as a diameter is a quick way to confirm a volume figure from a separate radius-based tool.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How volume changes with diameter at a fixed height
A fixed height of 20 units, across a range of diameters.
| Diameter | Volume | Total surface area |
|---|---|---|
| 4 | 251.327 | 276.460 |
| 8 | 1,005.31 | 603.186 |
| 10 | 1,570.80 | 785.398 |
| 15 | 3,534.29 | 1,295.91 |
| 20 | 6,283.19 | 1,884.96 |
| 30 | 14,137.17 | 3,298.67 |
How volume changes with height at a fixed diameter
A fixed diameter of 10 units, across a range of heights.
| Height | Volume | Total surface area |
|---|---|---|
| 5 | 392.699 | 314.159 |
| 10 | 785.398 | 471.239 |
| 20 | 1,570.80 | 785.398 |
| 30 | 2,356.19 | 1,099.56 |
| 50 | 3,926.99 | 1,727.88 |
| 100 | 7,853.98 | 3,298.67 |
Questions
Why not just halve the diameter and use the radius calculator?
You certainly can, and the answer is identical; this calculator simply saves that one manual step by accepting the diameter directly, which matches how most tape-measure and spec-sheet readings are already given.
Does this give the same answer as a radius-based cylinder calculator?
Yes, exactly, as long as the diameter entered here is twice the radius entered there. Both compute the same underlying formula, only starting from a different one of the two equivalent measurements.
What if I only know the circumference, not the diameter?
Divide the circumference by π to get the diameter first (circumference = π × diameter), then enter that result here.
Does this work for a hollow pipe or tube?
No, this gives the solid volume of a full cylinder. For a pipe with a wall thickness, an inner and outer diameter both need to be accounted for separately.
For a cylinder measured by radius instead, see the volume of a cylinder calculator. For a hollow tube or pipe with an inner and outer radius, see the hollow cylinder volume calculator.