Example
Input: 8ft 4in Rise
Result: 14 Risers @ 7.14", 13 Treads
Step-by-Step Guide
- Measure Rise: Vertical distance from finished lower floor to finished upper floor.
- Determine Steps: Tool divides rise by standard step height to find count.
- Calculate Run: Multiplies tread depth by number of treads.
- Stringer Length: Uses Pythagorean theorem (Rise² + Run²) to find diagonal.
What is Stair Calculator: Rise, Run & Stringer Layout?
Designing stairs requires precise math to ensure safety and comfort. This tool calculates the number of steps, individual riser height, and total run based on the total floor-to-floor height. It adheres to standard building codes (e.g., max 7.75" rise).
👷 Safety First: Always adhere to local building codes and regulations. Wear appropriate Personal Protective Equipment (PPE) when performing construction tasks.
How it Works
1. Measure 'Total Rise' (vertical height).
2. Divide by ideal riser height (~7 inches or 180mm) to get step count.
3. Round step count to nearest integer.
4. Recalculate exact riser height (Total Rise / Steps).
5. Calculate Run (Steps - 1) * Tread Depth.
FAQ
What is the ideal riser height?
Between 7 and 7.5 inches (180mm) is standard for comfort.
What is the minimum tread depth?
Codes usually require a minimum of 10 inches (254mm) for safe footing.
How to calculate stringer length?
It's the hypotenuse of the total rise and total run triangle.
What is headroom?
You need at least 6ft 8in (2m) of vertical clearance above the stair nosing.
Why subtract tread thickness?
To ensure the bottom step height matches the others after treads are installed.
Conclusion
Uneven stairs are a major trip hazard. This calculator ensures every step is identical within tolerance (typically 3/8 inch). Remember to account for the thickness of the tread material on the bottom step when cutting stringers.