Concrete Stair Calculator
Estimate a monolithic concrete stair from step count, rise, tread and width.
Enter your project details
Each dimension can use its own unit—for example feet for length and inches for thickness. Package counts are rounded up.
Formula and calculation steps
Volume = width × rise × tread × n × (n + 1) ÷ 2- Use 4 risers at 4 in and 120 in treads.
- Calculate the stepped volume.
- Add 10% allowance.
Worked example
Enter finished stair geometry. The calculator includes the stepped mass and the supporting wedge.
How to use this calculator
- Enter number of steps, rise, tread and stair width.
- Confirm units match the drawing.
- Use the volume result with waste before ordering concrete.
Example: Enter finished stair geometry. The calculator includes the stepped mass and the supporting wedge.
Questions about this calculator
Does this include the stringer/wedge under the steps?
Yes. The estimate includes the stepped mass and the supporting wedge for a monolithic pour.
Are landings included?
Enter only the stair run geometry here; calculate landings separately as slabs if needed.
Can I use mixed units?
Yes. Choose feet, inches, metres or centimetres and the calculator converts each input before calculating.
Is this a final material order?
No. Confirm drawings, product coverage, local code and site conditions before buying or building.
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<iframe src="https://www.buildcalclab.com/embed/stair-calculator/?theme=light" width="100%" height="640" title="BuildWise calculator" style="border:0;max-width:720px"></iframe>Assumptions and references
Results are estimates based on the dimensions and values you enter. Verify final quantities, manufacturer coverage and site-specific requirements before ordering.
Last reviewed: July 2026 · Read our calculation methodology