Free estimate — verify against local code before building
Concrete Stairs Calculator
Enter approved stair geometry to estimate monolithic concrete volume, bags, and optional cost.
What this calculator includes
Calculate the stepped concrete volume for a straight monolithic stair using the approved width, uniform rise, tread run, and the exact number of tread-depth layers in the stepped body. A top floor or landing is not silently counted as another layer; add its rectangular volume separately when it is part of the same placement.
Next step in your project
Check the placement weight and handling plan
Convert the stair and landing concrete volume into estimated wet or cured weight using an editable density.
Open Concrete Weight Calculator →How to use this concrete stairs calculator
- 01
Use approved stair dimensions
Enter the uniform finished rise, tread run, width, and number of modeled tread-depth layers from the project drawings or qualified design.
- 02
Add only the connected landing
Include a landing only when its rectangular volume is part of this concrete placement; calculate separate slabs or foundations independently.
- 03
Set the placement allowance
Edit waste for form variation, spillage, and supplier rounding without changing the designed stair geometry.
- 04
Compare purchase methods
Review ready-mix yards and bag counts, then verify product yield, delivery access, placement time, supplier minimums, and batch consistency.
Worked example
Example: three 4 ft wide steps with a landing
Three steps at 7 in rise and 12 in run produce 14 ft³ of stepped concrete at 4 ft wide. A 4 ft by 4 ft landing 6 in thick adds 8 ft³; with 10% waste, the order volume is 24.2 ft³ or about 0.90 yd³.
Practical buying and overage guidance
Coordinate concrete strength and exposure, reinforcement, forms, foundation, placement sequence, access, crew capacity, consolidation, finish, curing, weather protection, supplier minimums, and washout before scheduling material.
Continue the project
Pour a Concrete Slab
Plan slab excavation, base, concrete yards or bags, forms, reinforcement allowances, delivery, labor, equipment, and contractor pricing.
Open the project workflow →Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- NRMCA CIP 31 — Ordering Ready Mixed Concrete (opens in a new tab)
Ready-mix ordering and allowance context.
- ACI 318 Building Code Portal (opens in a new tab)
Structural-concrete requirements must come from adopted requirements and approved design.
Frequently asked questions
What formula does the concrete stair calculator use?
It adds the rectangular layers under each tread: stair width × step rise × tread run × n(n+1)/2. A selected landing is added as width × length × thickness.
Does this calculate stair riser or tread dimensions?
No. Rise, run, landings, handrails, guards, headroom, reinforcement, foundation, and egress requirements must come from approved project information.
Should the top landing be counted as another tread layer?
No. Count only the equal tread-depth prisms in the stepped body. Enter the top landing separately when its rectangular volume is included in the same placement.
Can I pour concrete stairs using bags?
Small placements may be practical with bags, but mixing rate, consistent water, placement time, consolidation, finishing, and curing still matter. Verify the product and planned placement with qualified guidance.
Does the estimate include footings or reinforcement?
No. It covers the entered stepped body and optional landing volume only. Foundations, reinforcement, dowels, forms, fill, and drainage are separate design and takeoff items.