Free concrete step calculator. Enter riser height, tread depth, number of steps, and stair width to estimate concrete volume, waist slab, landing, and material cost.
Calculates the total concrete volume required for straight-flight stairs including step blocks, waist slab, and optional landings.
V_{\text{total}} = \left[N \times (R \times T \times W)\right] + V_{\text{waist}} + V_{\text{landing}}
Each step is treated as a rectangular block: riser height × tread depth × stair width, multiplied by the number of steps. If you enter a waist slab thickness, the sloped slab under the steps is added (thickness × slope length × width), and an optional top landing is added as length × width × thickness. A waste margin is then applied and the result is priced at your ready-mix rate.
The waist slab is the sloped concrete slab that the steps sit on, spanning the full incline of the staircase. Freestanding exterior stairs usually need one (typically 4–6 in thick). If your steps are built over solid compacted fill or sit on an existing slab, enter 0 and the calculator estimates the steps alone.
Common residential guidance (e.g., IRC R311.7) limits risers to about 7¾ in (197 mm) and requires treads of at least 10 in (254 mm). Many builders aim for a comfortable 7 in riser with an 11 in tread. Always verify against your local building code before construction — requirements vary by jurisdiction.
No. This is a ready-mix material volume and cost estimate only. Reinforcement, formwork, subgrade preparation, placement labor, finishing, delivery and short-load fees are separate costs — get a written supplier quote before ordering.
Calculations are preliminary estimates for planning and education. Verify results against project documents and applicable codes with a licensed Professional Engineer. The interactive calculator loads automatically when JavaScript is available.