Stair Calculator

in
in

IRC residential maximum is 7 3/4 in.

in

IRC minimum is 10 in.

Riser height

7.714 in

Risers
14
Treads
13
Total run
130 in
Stringer length (diagonal)
169.01 in
Stringer board to buy
2 × 12 × 16 ft
Stair angle
39.7 °
Comfort check (2 × riser + tread, 24–25 ideal)
25.43 in
Meets IRC riser and tread limits
Yes

Treads = risers − 1 because the upper floor is the top step. Stringer length is the hypotenuse; buy at least a foot longer for end cuts.

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