If you are looking for the riser / tread ratio, an old copy of
Architectural Graphic Standards would be a help. The 5th Edition, pg
222 has a nice comparison of several formulae.
I use 2R+T = 25 (example: R=7" & T= 11" : 2 @ 7 + 1 @ 11 = 25)
Standards are great, that's why we have so many of them.
But if you're putting a stairway in a normal sized house,
the constraints of the available space will matter more
than any formula.
You divide the floor-to-floor height evenly into the smallest
number that yields less than 8" of rise per step.
Then you figure out how to cram that into the available
run, figuring no less than 10" and no more than 11.25"
of tread, and no more than 1" of overhang for the bullnose (if any).
And remember that you need 6'8" of overhead, measured from
the front of the treads.
California's rules are here:
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