Cylinder Volume Calculator

Cylinder dimensions

How it works

A cylinder is a circle stretched along a length. The circle's area is πr², so the volume is V = πr²h — base area times height. The total surface area counts both end caps and the wrapped-around side: A = 2πr² + 2πrh, which factors neatly as 2πr(r + h). The side alone (the label area on a can, the wall of a pipe) is 2πrh, reported separately above.

Liters and gallons are converted from the cubic volume with exact factors: 1 liter = 1,000 cm³, 1 cubic inch = 16.387064 ml, 1 cubic foot = 28.316846592 liters, and 1 US gallon = 3.785411784 liters. The radius/diameter choice is handled before any math — a diameter is simply halved.

Worked example: a cylinder of radius 10 cm and height 30 cm holds π × 100 × 30 = 9,424.78 cm³ — about 9.42 liters or 2.49 US gallons — with a total surface area of about 2,513.27 cm².

How this differs from the aquarium calculator: that tool answers a fish-keeper's question (tank capacity with a rectangular option and substrate weight). This one is the general-purpose geometry — round vessels of any kind, and the only one of the two that reports surface area.

Frequently asked questions

Is the height the same as the length? For a pipe or a log lying on its side, yes — "height" here is just the cylinder's long dimension, whichever way it points.

How much water is in a pipe? Treat the pipe as a cylinder using its inside diameter and its length. A 10-foot run of pipe with a 2-inch inside diameter holds π × 1² × 120 ≈ 377 cubic inches ≈ 1.63 US gallons.

Why is the end-cap area sometimes excluded? For open tanks and pipes the caps aren't material you buy; that's why the side (lateral) area is listed on its own — use the total when the cylinder is closed, like a can or a sealed drum.