Concrete Slab Calculator
Estimate concrete volume for a rectangular slab with an optional ordering allowance.
Your result
EVERYDAYEnter your values and select calculate.
On this page How it works & practical examples
How to use the Concrete Slab Calculator
Measure the slab footprint in meters and thickness in centimeters. The thickness is converted to meters before multiplying. The allowance is applied to the geometric volume rather than increasing each dimension, so a 10% allowance adds 10% volume. The result also shows cubic yards to help compare suppliers using a different volume unit.
The calculation
Worked example
A 10 m by 5 m slab, 10 cm thick, has a geometric volume of 5 m³. A 10% ordering allowance increases the quantity to 5.5 m³.
Assumptions and limits
The calculator models a solid rectangular slab of constant thickness. Footings, thickened edges, slopes, openings and irregular excavation are not included. It does not choose concrete strength, reinforcement, foundation depth or safe structural dimensions. The allowance is a planning choice, not a prescribed construction standard. Confirm ordering units and minimum quantities with the supplier.
Common questions
Why is thickness entered in centimeters?
Slab thickness is often measured that way. The calculator converts it to meters to keep the volume dimensionally consistent.
Does this tell me how thick the slab should be?
No. Thickness is an input decided for the project. Structural requirements require appropriate design guidance.