The calculation, without hidden assumptions
A solid concrete stair is not one thin tread multiplied by the number of steps. Each higher tread sits on the mass below it, so the staircase cross-section is the sum of stacked rectangles. MAXScanner uses that stepped-prism geometry, optionally adds a top landing extension at full stair height, then applies the allowance and bag yield you enter for a transparent purchase estimate.
How to use this calculator
Enter the number of equal steps, rise per step, tread depth and overall stair width.
If a solid top landing continues beyond the final tread, enter only that extra landing depth; otherwise leave it at zero.
Set an allowance and the actual premix bag yield to see cubic feet, cubic yards, whole bags and optional material cost.
Where people use it
- •Porch and entry-step concrete planning
- •Comparing stair widths or step counts
- •Checking bagged-mix quantity before a small solid stair pour
Example: four 7 in × 11 in steps, 4 ft wide
The stepped cross-section equals 7/12 × 11/12 × (4×5/2), then multiplies by 4 ft width. The result is the full solid staircase volume before allowance or any extra landing extension.
What the result does not assume
- •This is a simple solid stepped-prism model. Hollow stairs, fill cores, suspended stairs, reinforcement, foundations and formed landings need a project-specific quantity model.
- •Rise, tread, landing and structural requirements are governed by the actual design and applicable rules; this page does not certify stair-code compliance.
Frequently asked questions
Why not multiply one step block by the step count?+
That would undercount a solid staircase because higher steps include the concrete mass below them. The stacked-prism sum accounts for the full stepped profile.
What does extra landing depth mean?+
It is an optional horizontal extension beyond the final tread at the full stair height. Leave it at zero when there is no solid landing extension.
Does this check stair code?+
No. It estimates concrete volume only and keeps geometry separate from code or structural approval.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.