Concrete
Concrete Stairs Calculator
Calculate concrete volume for a solid concrete stair run using total rise, total run, width, and an optional landing. Get cubic yards, cubic feet, weight, and suggested order.
Inputs
Vertical distance from bottom finish to top finish.
Horizontal distance from nose of first tread to face of top riser.
Tread depth × (risers − 1) usually equals the total run.
Leave 0 to skip cost estimate.
Live estimate
Concrete required
1.57 cu yd
- Geometric volume
- 1.43 cu yd
- Total cubic feet
- 38.5 cu ft
- Stair (wedge) volume
- 38.5 cu ft
- Riser height
- 7 in
- Tread depth
- 11 in
- Suggested order
- 2 cu yd
- Approx. weight
- 6,353 lb
- Approx. weight (tons)
- 3.18 tons
- Estimated total
- $330
You will likely need
- •1.57 cu yd — concrete required
- •Approximate delivered weight: 6,353 lb
- •Estimated total: $330
Estimator guidance
Calculated quantity
1.43 cu yd
Suggested order
2 cu yd
Material behavior adjustment
+40%
Reason: Stairs concentrate finishing work at edges and noses — screed and form leakage regularly consume 8–12% more than the pure wedge geometry. Ordered up to the nearest 0.5 CY to match a practical ready-mix increment.
Estimator guidance based on how this material behaves in the field. The calculated quantity above remains mathematically correct — this is what an experienced estimator would order.
- Stair forms leak and settle during placement — screed and finishing losses run higher than for flatwork.
- Pumped placements typically require a larger buffer than direct-chute placements.
- Reinforcement, throat thickening, and haunches all consume additional volume vs the pure wedge geometry.
These are estimator recommendations, not a change to the underlying formula. The calculated quantity above remains mathematically correct.
- Verify field dimensions against drawings — poured stairs are rarely built to the exact drawing.
- Plan for reinforcement placement before the pour — cover, chairs, and dowels take time to set.
- Landings are often thickened at the wall interface — add that volume explicitly when estimating.
- Formwork complexity drives cost and time as much as concrete volume does — brief the crew on riser boards, kickers, and bracing.
- Estimating stair volume as a simple rectangular slab.
- Skipping the landing when the drawing has one.
- Ignoring throat thickening and pouring exactly the geometric wedge.
- Not verifying local code for riser height and tread depth before pouring.
How the concrete stairs formula works
A solid concrete stair run is modeled as a right-triangular prism (a wedge): the vertical face is the total rise, the horizontal face is the total run, and the depth is the stair width. Volume = 0.5 × rise × run × width.
Optional landings are simple slabs: length × width × thickness. Add both volumes for the total pour.
This model does not include throat thickening beneath the treads, form thickness, or reinforcement blockouts. Verify field dimensions and thickened sections before ordering.
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Material assumptions
- A solid concrete stair run is a right-triangular prism: V = 0.5 × rise × run × width.
- IRC residential guidance: max riser 7-3/4 in, min tread 10 in — always verify local code.
- Landings are a simple slab: length × width × thickness.
- This model does not include throat thickening beneath the treads, form thickness, or reinforcement blockouts.
Frequently asked questions
Related calculators
Stair dimensions, reinforcement, and guards are governed by local building code. Verify riser height, tread depth, minimum landings, and reinforcement with your AHJ or engineer before pouring.