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Estimate solid concrete steps and an optional landing using step count, riser height, tread depth, stair width, allowance, bag yield and supplier costs.
Concrete-step formulas
The formula models a solid staircase built from stacked equal rectangular steps. Hollow, suspended or irregular stairs require a different takeoff.
Worked example
Four steps that are 4 ft wide, 7 in high and 11 in deep contain about 21.39 ft³ before allowance. With 10% allowance, the order is about 0.871 yd³ or 40 bags at 0.60 ft³ per bag.
Visual guide
Measure finished dimensions. Calculate side walls, curbs, landings or foundations separately when their geometry is not included.
Planning checklist
- Confirm uniform finished rise and tread depth.
- Verify total rise against site elevations.
- Prepare and compact the supporting base.
- Brace forms against concrete pressure.
- Install reinforcement and dowels to approved details.
- Plan nonslip finish, drainage and curing.
The formwork estimate represents the two stepped sides plus all vertical riser faces. It excludes soffits and special edge forms.
Frequently asked questions
Does the calculator include a landing?
Yes. Enter landing length and thickness, or leave landing length at zero.
Why does each higher step add more concrete?
A solid staircase is modeled as stacked blocks, so upper steps sit on the concrete below.
Can this calculate hollow stairs?
No. Hollow or suspended stair systems need project-specific geometry.
Does this check building code?
No. Confirm rise, run, width, guards and handrails with local requirements.
Common mistakes
- Using total rise as one riser height.
- Forgetting the landing or foundation.
- Measuring outside form dimensions.
- Ignoring uneven subgrade and placement loss.