Stair Calculator
Calculate perfect stair dimensions for safe and comfortable stairs
Results:
| Number of Risers | - |
|---|---|
| Riser Height | - |
| Tread Depth | - |
| Number of Treads | - |
| Total Run | - |
Standard stair dimensions diagram
Advanced Results:
| Optimal Riser Count | - |
|---|---|
| Final Riser Height | - |
| Final Tread Depth | - |
| Stringer Length | - |
| Angle of Incline | - |
| Headroom Check | - |
Advanced stair measurements including stringer length
Spiral Stair Results:
| Number of Steps | - |
|---|---|
| Final Riser Height | - |
| Tread Depth at Center | - |
| Tread Angle | - |
| Total Rotation | - |
Spiral stair dimensions and measurements
Understanding Stair Calculations
What is a Stair Calculator?
A stair calculator is an essential tool for builders, architects, and DIY enthusiasts that helps determine the correct dimensions for safe and comfortable stairs. It calculates the optimal riser height, tread depth, and other critical measurements based on building codes and ergonomic principles.
Key Stair Measurements
- Riser: The vertical part between two treads (typically 6-8 inches)
- Tread: The horizontal part you step on (typically 10-11 inches deep)
- Total Rise: Vertical distance from floor to floor
- Total Run: Horizontal distance the stairs occupy
- Stringer: The structural support that holds the treads and risers
- Nosing: The protruding edge of the tread (typically 1-1.5 inches)
- Headroom: Clearance above the stairs (minimum 80 inches)
The 2R + T Formula
The ideal stair dimensions follow this formula for comfortable climbing:
This formula, developed based on average human stride, ensures stairs are neither too steep nor too shallow.
Building Code Requirements
Most building codes specify these requirements for residential stairs:
| Measurement | Minimum | Maximum | Ideal |
|---|---|---|---|
| Riser Height | 4 inches | 7.75 inches | 7-7.5 inches |
| Tread Depth | 10 inches | 14 inches | 10-11 inches |
| Width | 36 inches | - | 42-48 inches |
| Headroom | 80 inches | - | 84+ inches |
Why Use Our Stair Calculator?
Our tool provides accurate calculations for various stair types while ensuring compliance with building codes. Whether you're building new stairs or remodeling existing ones, this calculator helps you:
- Avoid costly mistakes in stair construction
- Create comfortable, safe stairs that meet building codes
- Calculate both standard and spiral stair dimensions
- Determine stringer length and angle
- Optimize space while maintaining safety
Types of Stairs You Can Calculate
Straight Run Stairs
Simple stairs that go directly from one level to another without turns.
L-Shaped Stairs
Stairs with a 90-degree turn, using a landing to change direction.
Spiral Stairs
Compact stairs that curve around a central pole, ideal for small spaces.