Stair Stringer Calculator
Stairs are the most code-sensitive thing in a house. Enter your total rise and run to get the step count, riser height, tread depth and stringer cut length — and whether the result actually passes.
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Results
Enter your measurements above and press Calculate.
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Questions people ask
How many steps for a 103 inch rise?
Fourteen risers at 7.36 inches each, which gives 13 treads. A 7.75 inch riser is the maximum allowed and 7 inches the minimum, so this one passes.
What is the maximum riser height for stairs?
7.75 inches for residential construction under the IRC. When the total rise exceeds 151 inches, the maximum drops to 7.25 inches. Below 7 inches is allowed but feels cramped.
What is the minimum tread depth?
10 inches for residential stairs measured as the nosing-to-nosing distance. Residential codes do not require a handrail on interior stairs under 3 feet, but it is strongly recommended.
Do I need a stair permit?
Almost always. Stairs are permitted work in most jurisdictions because a code failure can block a sale and is a liability risk. Check your local building department before cutting stringers.
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