Circular Slab Concrete Calculator

Calculate the amount of concrete needed in cubic feet and cubic yards for a slab in the shape of a circle.

To calculate the concrete volume needed for this type of slab, you need to know the circle's diameter and the depth of this slab..

Formulas

A = π * D²  ÷ 4

P = π * D

V = π * D² ÷ 4 * (d ÷ 12)

where A is the area in square feet, p = 3.14159265358979, D = diameter of circle
P is the perimeter in lineal feet, p = 3.14159265358979, D = diameter of circle
V is the volume in cubic feet, p = 3.14159265358979, D = diameter of circle, d = depth of slab in inches ÷ 12 converting this to feet

To convert cubic feet to cubic yards, multiply cubic feet * 0.037037037037037
To convert cubic feet to cubic metres, multiply cubic feet * 0.028316846592
To convert cubic yards to cubic metres, multiply cubic yards * 0.764554857984

Example calculation

Diameter of slab = 12 feet
depth of slab = 4 inches

3.14159 * 12² ÷ 4 = 3.14159 * 144 ÷ 4 = 113.1 (rounded to one digit)

The area of the slab is 113.1 square feet

3.14159 * 12 = 37.6 (rounded to one digit)

This slab has a circumference of 37.7 feet

3.14159 * 12² ÷ 4 * (4 ÷ 12 ) = 3.14159 * 144 ÷ 4 * 0.333 = 37.7 (rounded to one digit)

>The volume of this slab is 37.7 cubic feet

You will need 37.7 * 0.037 = 1.4 cubic yards of concrete to pour this slab.