Stair Calculator
Free online stair calculator for construction and renovation. Calculate number of steps, rise, run, total length, and angle. Verify against building codes for safe and comfortable staircase design.
Staircase Parameters
What is a Stair Calculator?
A Stair Calculator is an essential tool for architects, builders, and homeowners to design safe and comfortable staircases. It calculates the optimal number of steps, rise height, run depth, total horizontal length, staircase angle, and verifies compliance with building codes. Proper stair design is crucial for safety, accessibility, and user comfort.
Building Code Standards (General Guidelines)
- Rise (vertical height of each step): 150mm - 220mm
- Run/Going (depth of each step): 220mm - 355mm
- Comfort formula: 2 × Rise + Run = 600-650mm
- Maximum rise variation between steps: ±5mm
- Minimum stair width: 800mm (residential), 1000mm (commercial)
- Minimum headroom clearance: 2000mm
- Maximum angle: 42° for residential stairs
- Handrail required for stairs with more than 3 risers
Calculation Formulas
Number of Risers:
Number of Risers = Total Rise / Ideal Rise (rounded)
Actual Rise per Step:
Actual Rise = Total Rise / Number of Risers
Total Run (Horizontal Length):
Total Run = (Number of Risers - 1) × Run
Comfort Formula:
2 × Rise + Run = 600-650mm (comfort rule)
Tips for Stair Design
- Ideal rise is typically 175mm for comfortable climbing
- Ideal run is typically 280mm for adequate foot space
- The 2R+G rule (600-650mm) ensures comfortable stairs
- Steeper stairs (higher rise, shorter run) are harder to climb
- Gentler stairs (lower rise, longer run) are easier but take more space
- Always maintain consistent rise and run throughout the staircase
- Consider adding a landing for stairs with more than 16 steps
- Local building codes may have specific requirements - always check
Staircase Terminology
- Rise: The vertical height of each step, measured from the top of one tread to the top of the next
- Run (Going): The horizontal depth of each step where you place your foot
- Total Going: The total horizontal length of the staircase from first to last step
- Pitch (Angle): The angle of the staircase relative to the horizontal, typically 30-42° for residential stairs
- Headroom: The vertical clearance from the tread nosing to the ceiling or obstruction above, minimum 2000mm