Concrete Cylinder Volume Calculator

Many concrete shapes are cylinders: round columns and piers, post holes, form tubes, manhole rings and pipes, and the 4 × 8 in or 6 × 12 in test cylinders that labs crush to check strength. Enter the diameter and height in whatever units you measured, add an inside diameter for a hollow cylinder, and the calculator gives the volume in cubic feet, cubic yards, litres and cubic metres, the approximate weight and the number of premix bags.

How to use this tool

1. Enter the outside diameter and choose its unit.
2. Enter the height or depth and its unit — they can differ, such as inches and feet.
3. For a pipe or ring, enter the inside diameter; leave 0 for a solid cylinder.
4. Enter how many identical cylinders there are and any waste allowance.

Formula

V = π × (D² − d²) ÷ 4 × h × n

D is the outside diameter, d the inside diameter (0 for a solid cylinder), h the height and n the number of cylinders. Working from the diameter avoids a common slip: π × D² × h, without dividing by 4, overstates the volume four times.

Example

A standard 6 × 12 in test cylinder holds π × 6² ÷ 4 × 12 = 339.3 in³, which is 0.196 ft³ or 5.56 litres, and weighs about 29 lb at normal concrete density. A 12 in form tube filled 4 ft high holds 3.14 ft³ (0.116 yd³), which takes 6 bags of 80 lb premix.