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Stair Geometry Calculator
Lay out equal risers from total rise and a user-selected maximum riser height.
Total floor-to-floor rise (m), Maximum desired riser (m), Horizontal going per tread (m)
JSON
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the labelled values and use the displayed units.
- Choose Calculate result and inspect the full report, assumptions and undefined/no-solution status.
- Choose Download result to save the complete JSON. Reset clears results and restores the example controls.
Examples
Total floor-to-floor rise (m): 2.8
Maximum desired riser (m): 0.18
Horizontal going per tread (m): 0.25
Limitations
- Total rise and maximum riser in metres; at least two and at most 1000 risers. Upper floor is the final landing, so treads=risers-1; going supplied. No building-code, headroom, nosing, stringer cutting or safety certification.
- Scalar numeric inputs use explicit decimal syntax and IEEE-754 arithmetic; unless a tighter bound is stated, positive values are 1e-12–1e12 and nonnegative values 0–1e12. Derived inventory counts above 1 billion and nonfinite results are refused. Combined input limit400,000 UTF-8 bytes;complete JSON output limit4MiB. Numeric/code input controls allow128 characters. All processing stays in your browser.
- Whole purchasing/layout counts use exact entered decimal quantities for rational formulas; circular geometry remains floating-point.
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