Stair Calculator
Calculate step dimensions for comfortable and code-compliant stairs. This tool helps you determine the rise, run, angle, and stringer length for your stair project. Choose between basic and comprehensive versions below.
Basic Version
Comprehensive Version
Standard range: 6-7.75 inches
Basic Stair Calculation Results
| Measurement | Value |
|---|---|
| Number of Steps | 0 |
| Actual Rise per Step | 0 in |
| Run per Step | 0 in |
| Stringer Length | 0 in |
| Angle | 0° |
Stair Building Tips
- Optimal rise/run ratio is around 7.5/10 inches
- Minimum run is typically 10 inches
- Maximum rise is usually 7.75 inches
- Headroom should be at least 6'8"
Comprehensive Stair Calculation Results
| Measurement | Value |
|---|---|
| Number of Steps | 0 |
| Actual Rise per Step | 0 in |
| Actual Run per Step | 0 in |
| Stringer Length | 0 in |
| Angle | 0° |
| Headroom Height | 0 in |
| Total Material Needed | 0 linear feet |
About Stair Calculations
Properly designed stairs are essential for safety and comfort in any building. This calculator helps you determine the optimal dimensions for your stairs based on standard building codes and ergonomic principles.
Key Stair Measurements
- Rise: The vertical height of each step. Standard range is 6-7.75 inches.
- Run: The horizontal depth of each step. Minimum is typically 10 inches.
- Total Rise: The overall vertical height from one floor to the next.
- Total Run: The overall horizontal length of the stairway.
- Stringer: The structural support that holds the treads and risers.
Stair Building Codes
Most building codes follow these general guidelines:
International Residential Code (IRC)
- Maximum rise: 7.75 inches
- Minimum run: 10 inches
- Maximum variation between risers: 3/8 inch
- Minimum headroom: 6 feet 8 inches
Occupational Safety and Health Administration (OSHA)
- Maximum rise: 9.5 inches
- Minimum run: 9.5 inches
- Maximum angle: 50 degrees
Stair Design Formulas
The following formulas are used in stair calculations:
- Number of Steps: Total Rise ÷ Desired Rise (rounded up)
- Actual Rise: Total Rise ÷ Number of Steps
- Stringer Length: √(Total Rise² + Total Run²)
- Angle: arctan(Total Rise ÷ Total Run)