Concrete Stairs Calculator
Estimate the material in a solid set of uniform concrete steps with a flat underside. The tool sums the stepped cross-section instead of treating the stair as one rectangular block.
How the calculation works
For n equal steps, stepped cross-section area = tread run × riser height × n(n + 1) ÷ 2. Multiply by stair width. Convert all inches to feet first, then divide cubic feet by 27.
Worked example
Five solid steps, 4 ft wide, with 10 in tread run and 7 in riser height contain about 29.17 ft³ or 1.08 yd³. At 10% extra, that is 1.19 yd³ or 54 bags at 0.60 ft³ yield.
Before you order
This geometry assumes the space below the steps is filled with concrete. A sloped underside, void, landing, thickened base or separate foundation changes the volume. Confirm the formwork and structural details with your plans.
Review the calculation method and source notes, then use the supplier checklist before placing an order.
A solid stair example
This tool treats the entire stair flight as solid concrete, so the volume is the sum of stepped rectangular prisms. For each step, the filled height increases by one rise. The sum of heights is rise × n(n + 1)/2, where n is the number of steps. This assumption is inappropriate for a hollow, precast or separately supported stair.
Check finished width, run and rise after formwork is set. If a landing is separate, calculate it as a rectangular slab in the multi-pour estimator. Do not count the landing as an extra tread and a slab simultaneously.
Questions before you order
Does this include a landing?
No. Add the landing as a separate rectangular pour so its volume is counted once.
What if the stairs are hollow underneath?
This calculator assumes solid fill and would overstate concrete. Measure the actual concrete cross-section or use project drawings.
Does this choose a safe riser height?
No. It estimates material volume only. Stair dimensions and reinforcement must follow the applicable design and code.
Continue planning
Content and calculator by pourmeasure. Formula and assumption notes: methodology and sources. Updated October 2026. No independent engineering review is claimed.