Stair Stringer Layout (with code check)
Riser count, exact rise, total run, stringer hypotenuse, throat depth, and pass/fail against your AHJ's max rise / min tread.
Formula and source
Riser count = ceil(total_rise / target_rise). Exact rise = total / count. Total run = (count − 1) × tread. Stringer hypotenuse = sqrt(rise² + run²). Throat depth = stringer_thickness × cos(theta) − exact_rise × sin(theta) where theta = atan2(rise, run). Pass/fail against user-entered local-code rise max and tread min.
IRC 2021 (International Residential Code). §R311.7 referenced by name; the user supplies the AHJ's adopted max rise and min tread (the tile does not bundle code values).
Audience
This tile is built for carpentry and the adjacent professions in the Carpentry and Construction group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
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Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.