Construction

Concrete Stairs Calculator

Estimate concrete for a flight of stairs.

Number of steps

Step rise

Step run

Stair width

Calculated Output

Concrete volume 0.0868

Volume 0.0032

80 lb bags 1

Formula: volume ≈ ½ × total rise × total run × width

Step-by-Step Breakdown

1. Values used:

2. Number of steps = 5

3. Step rise = 1

4. Step run = 1

5. Stair width = 1

7. Concrete volume = 0.0868

8. Volume = 0.0032

9. 80 lb bags = 1

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The math behind it

The solid under the steps is a triangular prism: ≈ ½ × total rise × total run × width (in feet).

5 steps (7 in rise, 11 in run), 4 ft wide → ~5.3 ft³.

Open underneath?

Hollow/formed stairs use much less — this assumes a solid pour.