This quantity model represents monolithic solid steps. It does not model suspended stairs, separate stoops, voids, nosings, foundations or structural reinforcement.
01 / Formula
How this is calculated
Stair volume = width × tread × riser × n(n + 1) ÷ 2; add landing volume02 / Assumptions
What the estimate assumes
- ✓Every tread and riser is equal.
- ✓The stair mass is solid.
- ✓Landing thickness is uniform and foundations are excluded.
03 / Worked example
See the math in context
Four solid steps, 4 ft wide, with 11-in treads and 7.5-in risers form ten tread-riser volume units before adding a landing.
04 / Guidance
Use designed stair dimensions
Rise, run, landings, guards and handrails are safety-critical. Enter dimensions from approved project information; this calculator does not design stairs.
Questions
Frequently asked
Should I order exactly the calculated amount?+
Usually no. Excavation variation, form dimensions, spillage, and uneven subgrade can increase actual volume. Use the editable waste allowance and discuss minimum loads and order increments with the supplier.
How many cubic feet are in a cubic yard?+
There are exactly 27 cubic feet in one cubic yard. Divide cubic feet by 27 to convert to cubic yards.
Does this replace a structural design?+
No. These tools estimate material quantity only. A qualified professional and applicable plans, codes, site conditions, reinforcement requirements, and manufacturer instructions govern the project.
Sources