Spike's Calculators


Stair Well Floor Opening Size

Calculate the size of the floor opening based on required headroom.

Note: Keep in mind that the required headroom must allow for finished surfaces.

Spike's Calculators

Stair Well Opening

Rise in n
Run in n
Floor Thickness in n
Required Headroom ft in
Dimension of Nosing in n


Opening Size ft in

The Calculator

  1. riser height (unit rise)
  2. run depth (unit run)
  3. thickness of floor structure (floor finish material plus joist plus plywood plus ceiling finish)
  4. required headroom
  5. nosing, the amount the stair tread projects passed the vertical riser below (if there is any)

The Results

  1. the length of the opening in the upper floor
If you have any questions or comments please Contact Us
Privacy Policy
© 1998, VmNet.