Stair Calculator.
Lay out risers, treads and stringer length, checked against OSHA 1910.25 or the IBC.
Industrial / workplace stairs installed after 17 Jan 2017
- Risers
- 16
- Treads
- 15
- Total run
- 13.75 ft
- Stringer length
- 16.43 ft
- Flights needed
- –
Limits from: 29 CFR 1910.25(c)(1)–(3): 30–50°, riser ≤ 9.5 in, tread ≥ 9.5 in. For information only, not a design or compliance check. Check the code edition adopted where the work is built and have a licensed professional verify it.
How to use it
- Pick the standard you design to: OSHA 1910.25 for industrial stairs, IBC for commercial buildings, or IBC dwelling units.
- Enter the total rise (floor to floor), the riser height you would like, and the tread depth, all in inches.
- Read the riser height, tread depth, pitch and rise per flight against the limits shown, and the number of risers, treads, total run and stringer length below them.
Example
A 108 in rise with a 7 in preferred riser and an 11 in tread gives 16 risers of 6.75 in, 15 treads, a 13.75 ft run, a 31.5° pitch and a 16.4 ft stringer. That is within the OSHA, IBC and IBC dwelling limits.
Source and notes
- The number of risers is rounded up, so the riser never exceeds the height you entered.
- Limits: OSHA 29 CFR 1910.25 (riser up to 9.5 in, tread at least 9.5 in, 30° to 50°); 2021 IBC section 1011.5.2 (riser 4 to 7 in, tread at least 11 in, at most 12 ft of rise per flight); dwelling units (riser up to 7¾ in, tread at least 10 in).
- Always check the code edition adopted where the work is built.
More tools
Unit Converter
Convert between mm, cm, m, inches, feet and yards, with fraction and feet-inch entry.
Open tool →Feet-Inch Calculator
Add, subtract, multiply and divide in feet, inches and fractions.
Open tool →AISC Bolt Reference
Hole and slot sizes, minimum bolt spacing and minimum edge distance by bolt diameter.
Open tool →DisclaimerEducational use only. Not engineering, legal or code-compliance advice.
The content on StructuralWorld, including articles, diagrams, calculators and other tools, is provided for general educational and informational purposes only. It is not engineering, architectural, legal or code-compliance advice, and it does not create a professional relationship between you and StructuralWorld or its authors.
Codes, standards and regulations (for example OSHA, IBC, ADA and AISC) are revised regularly and are adopted and amended differently by each jurisdiction. Figures shown here may be simplified, may refer to a specific edition, and may be out of date or contain errors. Calculators and interactive diagrams are illustrative only and are not a substitute for design calculations, shop drawings or engineering review.
Before relying on any information for design, fabrication, erection, inspection or safety decisions, verify it against the current governing code and the project documents, and consult a qualified, licensed professional (such as a structural engineer) and the authority having jurisdiction.
To the fullest extent permitted by law, StructuralWorld and its authors make no warranties, express or implied, about the accuracy, completeness or fitness for a particular purpose of this content, and accept no liability for any loss, damage or injury arising from its use or from reliance on it. Links to third-party standards and websites are provided for convenience; that material belongs to its owners. If you find an error, please let us know.