All Calculators/Stair Calculator

Stair Calculator

Calculate rise, run, stringer length, and IBC code compliance for any staircase.

The stair calculator takes total rise and your preferred riser/tread dimensions to compute the optimal step layout. It checks the result against IBC code limits so you know before you build whether the design will pass inspection. Use it to finalize stringer length and total horizontal run.
  • IBC requires risers between 4 and 7 inches and treads at least 11 inches — verify local code before deviating.
  • All risers in a flight must be within 3/8 inch of each other or the stair fails inspection.
  • Add 1 inch to stringer length when cutting to allow for the bottom tread plumb cut.
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