calcs.homes
calcs.homes
Enter your step count, riser height, tread depth, and stair width to find how much concrete a solid stair pour needs.
Estimate only — excludes a separate footing below the stairs, if your design needs one.
A solid concrete staircase has a stepped cross-section — each step is a smaller rectangle stacked on the one below it. Summing those rectangles gives cross-sectional area = riser × tread × steps × (steps + 1) ÷ 2, the same triangular-number pattern used to sum 1 through n. We multiply that area by stair width for total volume, then convert to cubic yards and 60 lb bags.
This treats each step as solid concrete from the bottom riser up, matching how most outdoor stair pours are formed and poured in one shot rather than built as a hollow shell. It doesn't include a separate footing below the stairs — codes in frost-prone areas usually require one below the frost line so the stairs don't heave or settle — add that separately with the concrete calculator's footing mode if your design calls for one.
It depends on the number of steps, riser height, tread depth, and width — enter your specific stair dimensions above for an exact cubic yard figure.
Most codes require a footing below grade, sized for your local frost depth, to keep the stairs from heaving or settling — check with your local building department.