Built for a fast architecture workflow
- Riser count
- Actual riser height
- Tread count
- Total horizontal run
- Stair angle
- 2R + T proportion check
Stair Calculator for Risers, Treads & Run
Turn floor-to-floor height and a target riser into a practical first-pass stair layout. The calculator rounds to a whole riser count, then recalculates the actual riser height and overall stair geometry.
How to use it in practice
For a 2800 mm floor-to-floor height with a 175 mm target riser, the calculator gives 16 risers at 175 mm each. With 280 mm treads, 2R + T equals 630 mm, inside the tool’s 600–650 mm comfort check range.
How to use Stair Calculator for Risers, Treads & Run
- 1
Enter the total floor-to-floor height in millimetres.
- 2
Enter your target riser height and proposed tread depth.
- 3
Calculate to get the nearest whole number of risers and the resulting actual riser.
- 4
Review the total run, angle and 2R + T result before developing the stair further.
Common questions
Why does the actual riser change?
The floor height has to be divided into a whole number of equal risers, so the calculator rounds the riser count and recomputes the exact height.
What is the 2R + T rule?
It is a common stair proportion check: two riser heights plus one tread depth are often assessed around a comfortable range. The tool flags 600–650 mm as its comfort range.
Does this check building code?
No. Verify minimum tread, maximum riser, headroom, width, landings, guards and all other requirements under the applicable code.
Related architecture tools
ARCHITEAM WORKSPACE
Open Stair Calculator for Risers, Treads & Run →Use the calculator or tool directly in your browser.
Your existing ArchiTeamTools workspace opens with this tool selected.