Stair Riser Calculator
Calculate basic stair dimensions from floor-to-floor rise, target riser height, and tread depth.
How to use
- Enter total rise, target riser height, and tread depth in cm.
- Calculate risers, actual rise, tread count, total run, angle, and 2R+T.
Capabilities and scope
The runner rounds to a whole riser count near the target, then recomputes equal actual riser height.
How it works
risers=round(totalRise/targetRiser), actualRiser=totalRise/risers, treads=risers−1, run=treads×tread.
Example
A 280cm floor rise with target 18cm and 25cm tread is converted to a whole-riser layout.
Useful for
- Explore preliminary stair geometry
- Compare riser targets with total horizontal run
Before you use it
- It does not enforce local building-code limits for risers, treads, rails, or headroom and is not a construction approval tool.
Frequently asked questions
Does the actual riser stay exactly at my target?
No. It is recalculated so all risers divide the total floor height equally.