Total rise in, a code-checked stair layout out — steps, riser height, tread depth, run, stringer length, and angle. Then send it straight into a quote.
Ballpark, not gospel. This computes stair geometry from your rise and tread inputs — local code can differ from the IRC baselines shown, so confirm with your inspector before cutting.
Straight answers, no fluff. Then run your own numbers above.
Divide the total floor-to-floor rise by your target riser height — typically 7 inches — and round to the nearest whole number. Then divide the actual rise by that step count to get the exact riser height, which must stay within ⅜″ of uniform. The calculator above does this and flags code issues automatically.
The International Residential Code allows a maximum riser height of 7¾ inches and a minimum tread depth of 10 inches. The comfortable sweet spot most carpenters use is a 7-inch riser with an 11-inch tread.
Stringer length is the hypotenuse of the total rise and total run: square both, add them, and take the square root. For a 36-inch rise with 13 steps on 11-inch treads (143-inch run), the stringer is about 147.5 inches — roughly 12.3 feet.
A simple straight stair run costs roughly $1,000–$3,000 installed in 2026, depending on material and finish — pressure-treated deck stairs run lower, hardwoods and finished interiors run higher. Two 2×12 stringers are the minimum; stairs wider than 36 inches need a center stringer.
Related guides: Deck Stairs Cost · Deck Repair Cost · Cost to Install Deck Boards
Got your stair math? Turn this estimate into a professional quote and send it before you leave the job site.