Stair Calculator
Calculated using standard mathematical and industry formulas.
Free online Stair Calculator calculator and unit conversion tool for everyday, engineering, and home projects.
How to use this calculator?
- Enter total vertical rise.
- Enter target riser height.
- Read risers, run, and stringer length.
Formula & calculation method
Stair Geometry
Risers = Rise / Target Riser · Stringer = √(Rise² + Run²)
IRC building code model.
Step-by-step calculation example
120 inch rise → 16 risers @ 7.5 inch, 192.1 inch stringer.
Key insights to remember
- Max riser 7.75", min tread 10" (IRC).
How to interpret your results?
Stringer Length
Diagonal support board length.
Frequently asked questions
- How do I use the Stair Calculator calculator?
- Enter your numerical input and select desired units to get instant accurate results.
- How accurate are the conversions?
- Conversions use official ISO conversion factors for maximum precision.
- Does it convert metric and imperial units?
- Yes, seamless conversions between metric (meters, kg) and imperial (feet, lbs) are supported.
- Is my data stored?
- No, all calculations execute 100% locally in your browser with zero data logging.
- Can I use this for DIY or engineering projects?
- Yes, it provides reliable estimates for construction, crafting, science, and everyday math.
- What if I enter invalid inputs?
- The calculator will display a friendly error prompt if non-numeric values are entered.
Related calculators
See all other calculators · Explore all online calculators