Spike's Calculators


Circular Slab Concrete Calculator Using Metric Measures

Calculate the amount of concrete needed for a circular slab, using metric measurements.

To make this calculation you need to know the diameter of the circle in metres and the required depth of this slab in millimetres.

Calculator For Circular Slab
A = π * D²  ÷ 4
where A is the area in square metres, π = 3.14159265358979, D = diameter of the circle

P = π * D
where P is the perimeter in metres, π = 3.14159265358979, D = diameter of circle

A * (d ÷ 1000)
Where A is the area  metres, d the depth in millimetres
Example calculation;:
Diameter of slab = 24.6 metres
depth of slab = 100 millimetres

Calculate the square metres of the slab using the area formula;
3.14159265358979 * 24.6 * 24.6 ÷ 4 = 475.29
This slab has an area of 475.29 square metres;

Calculate the circumference of the slab using the perimeter formula;
3.14159265358979 * 24.6 = 77.28
The circumference of the slab is 77.28 metres.

Calculate the amount of concrete needed by multiplying the area by the thickness of the slab;
475.29 * (100 ÷ 1000) =
475.29 *  0.1 = 47.529
You need 47.529 cubic metres for this slab.

To convert cubic metres to cubic yards, multiply cubic metres * 1.30795061931439
To convert cubic metres to cubic feet, multiply cubic metres * 35.3146667214886

Circular Concrete Slab - Metric

Diameter m
Depth mm
Area of Slab
Perimeter of Slab m

Amount of Concrete Needed in:

Cubic Metres
Cubic Yards yd³
Cubic Feet ft³


  1. enter the diameter of the slab in metres
  2. slab depth in millimetres


  1. area of slab in square metres
  2. perimeter of slab
  3. concrete needed in cubic metres
  4. concrete needed in cubic yards
  5. concrete needed in cubic feet

When Ordering Concrete

This concrete calculator will help you in estimating the amount of concrete needed for your project. The amount given as needed, does not include any waste. It is recommended, depending on the job you are doing, to add anywhere from an extra 4% to 10% to your concrete order to make sure you have enough concrete to finish the job. Ask when ordering the concrete. They will be able to give you a good idea of what is needed.
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