How many risers do I need?

Divide the total rise by a target riser height, then round to a whole number and recheck the resulting riser height.

What is a comfortable stair angle?

Many residential stairs fall roughly in the 30-37 degree range, but code compliance depends on riser, tread, headroom and local rules.

Does this generate construction drawings?

No. It is a planning calculator. Final stairs need local code checks, stringer sizing, fastening, guards and handrails.

Stair Calculator

Calculate stair risers, treads, angle, stringer length and tread material from total rise and run in U.S. units.

English stair calculator for straight residential stairs. Enter total rise and total run in inches, then estimate riser height, tread depth, stair angle, stringer length, board feet, and material cost.

Total rise, in

Total run, in

Tread thickness, in

Stair width, in

Price, USD/BF

Tread material

Calculate a straight stair layout

Use this stair calculator for a straight residential stair layout: total rise, total run, riser count, tread depth, stair angle and stringer length. It focuses on the measurements homeowners and builders commonly check before laying out stringers.

R i ser = \frac{T o t a l r i se}{N u mb er o f r i ser s}

T r e a d = \frac{T o t a l r u n}{N u mb er o f t r e a d s}

S t r in g er = R i s e^{2} + R u n^{2}

Code and safety checks

The IRC commonly limits residential riser height and requires adequate tread depth, but local amendments can differ.
All risers in a stair flight should be consistent; small differences can create trip hazards.
Headroom, guards, handrails, landings, openings and structural support are outside this simple geometry estimate.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: May 29, 2026

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