Donut Shape Concrete Calculator - Metric
Calculate the amount of concrete needed in cubic metres and cubic yards for a donut shaped footing or slab.
Note: this is a circular area with a circular hole on the inside, not a torus!!
To be able to calculate the concrete volume needed for this type of footing you need to know the outer diameter of the circle, the inner diameter and the required depth.
Formula's used:
Total AreaA = π * D² ÷ 4
where A is the area in square metres, π = 3.14159265358979, D = outer diameter of circle
Perimeter P = π * D ÷
where P is the perimeter in meters, π = 3.14159265358979, D = diameter of circle
Volume
V = π * D² ÷ 4 * d
where V is the volume in cubic metres, π = 3.14159265358979, D = diameter of circle, d = depth of slab in millimetres
Volume calculation example:
outer diameter = 20 metres inner diameter = 19 metres depth of slab = 100 millimetres 3.14159265358979 * 20 * 20 ÷ 4 ( 100 ÷ 1000) = 31.4 cubic metres 3.14159265358979 * 19 * 19 ÷ 4 ( 100 ÷ 1000) = 28.4 cubic metres 31.4 - 28.4 = 3 cubic metres of concrete needed for this footing
To convert cubic metres to cubic yards multiply cubic metres * 1.31
To convert cubic metres to cubic feet multiply cubic metres * 35.32
To convert cubic yards to cubic feet multiply cubic yards * 27
Donut Shape Concrete Footing/Slab - Metric
Calculation
- enter the outer diameter in metres
- enter the inner diameter in metres
- the required depth in millimetres
Results
- width of footing or slab in metres
- square metres of this area (in case it is a slab)
- inside perimeter in metres
- outside perimeter, the circumference in metres
- combined perimeter the outside plus the inside added together
- concrete needed in cubic metres
- concrete needed in cubic yards
- amount of 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.Concrete Volume Calculators
Imperial
Metric
Shapes using Imperial & Metric Measurements
- Circle
- Circle - Metric
- Donut
- Donut - Metric
- Ellipse
- Ellipse - Metric
- Equilateral Triangle
- Equilateral Triangle - Metric
- Octagon
- Octagon - Metric
- Oval
- Oval - Metric
- Pentagon
- Pentagon - Metric
- Scalene Triangle
- Scalene Triangle - Metric
- Stadium Shape
- Stadium Shape - Metric
- Trapazoid
- Trapezium
- Plastic Concrete Footing Form