Can any builders tell me how far their stair nosing overhangs? I've read that 1.25" is common.

I'm having my stairs rebuilt and the overhang will affect the location of the bottom stair. Also, do you include the overhang amount when measuring the run of the stair? My stairs are going to be 8.1" tall due to lack of headroom and if the run is too long they will not be within the inch of (2X rise)+run=25. I want to make sure I'm measuring the run correctly so they are comfortable.

  • Is this interior or on a deck/entry? What will the stairs be finished with?
    – JPhi1618
    Mar 7, 2018 at 16:59
  • Its interior stairs with pine treads
    – Mike L
    Mar 7, 2018 at 17:58
  • What does within the inch of (2X rise)+run=25 mean?
    – isherwood
    Mar 7, 2018 at 19:56
  • This is a formula used to make sure stairs are in a comfortable rise/run.
    – Mike L
    Mar 8, 2018 at 0:06

2 Answers 2


1" to 1-1/4" is fairly standard regardless of location, but it's mostly personal preference. You don't normally consider the nosing when working out rise and run, as they typically only apply to the stringers (which have no nosing).

Even if the nosing was considered, the rise and run don't change since you'd measure from one nose to the next.


Code requires a nosing to be not more than 9/16” if it’s rounded and shall not extend less than 3/4” or more than 1 1/4”. Nosings shall be approximately the same amount and not vary by more than 3/8” from smallest to largest. (See ICC Section R311.7.5.3.)

However, nosings are not required if the tread is 10” or more. (See R311.7.5)

  • Oh, this is for residential construction. Commercial/industrial/etc. is different and probably needs to be ADA approved.
    – Lee Sam
    Mar 8, 2018 at 0:13

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