Concrete Stairs Calculator

What this concrete stairs calculator is estimating

Concrete stair estimating is often done from the stair profile rather than from a single rectangular block. A stepped staircase gains volume with each rise and tread, so the profile area builds up across the flight and then extends across the full stair width to create the concrete volume.

That makes this calculator useful for solid stepped stair pours where the rise, tread, and width repeat consistently. Instead of returning only a raw cubic-measure figure, it also shows the total rise and total run so you can sense-check the geometry while you plan the concrete order.

Core stair-volume formulas

The calculation treats the stair as a stack of repeated rises and treads. It first solves the stepped stair profile area from the number of steps, rise, and tread, then multiplies that profile by the stair width and finally applies the waste allowance to reach the ordering volume.

How to use the staircase concrete estimate

Use the total volume for procurement, the total rise and run to sense-check the staircase against the intended geometry, and the bag counts only as planning comparisons before you price bagged concrete against ready-mix. The result is especially useful for small exterior steps and simple cast stair flights where the step geometry repeats consistently.

For example, a 10-step stair with 7-inch rise, 11-inch tread, and 48-inch width needs about 4.79 cubic yards of concrete after a 10% waste allowance. That is large enough that a ready-mix quote is usually worth comparing before you commit to bag mixing.

What this result does not cover

This tool estimates a solid stepped stair flight only. It does not model separate landings, waist slabs, stringer voids, reinforcement, nosing details, or any staircase where the rise, tread, or width changes along the flight. It also assumes the concrete section is represented by the stepped solid rather than a more detailed structural shape.

Use the estimate for early ordering and planning, then confirm the final pour quantity from the detailed stair drawing and formwork layout before ordering concrete.