Stair Stringer Calculator
Calculate rise, run, tread depth, and stringer dimensions for building stairs. Checks against standard building code.
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ft
Vertical height to climb
ft
Horizontal distance available
in
36 inch minimum for most codes
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Frequently Asked Questions
What is the code for stair rise and run?
Most building codes require a maximum riser height of 7-3/4 inches and minimum tread depth of 10 inches. The riser-tread formula (2R + T) should equal 24-25 inches.
How many stringers do I need?
Three stringers is standard for stairs up to 36 inches wide. Add one stringer for every 16 inches of additional width.
What board do I need for stringers?
Use 2x12 lumber for stringers. The board must be longer than the diagonal distance from top to bottom of the stair.
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