Stair Calculator
Updated Formulas shown
Enter the total rise from finished floor to finished floor. A 105 in rise gives 14 risers of 7½ in and 13 treads — comfortably within the IRC limits (7¾ in max riser, 10 in min tread).
Steps (risers)
14
7.5 in each
- Riser height
- 7.5 in
- Treads
- 13
- Total run
- 136.5 in11.38 ft
- Stringer length
- 14.35 ft
- Stair angle
- 37.6°
- IRC residential code
- Meets 7¾ in / 10 in
The formula
Risers = total rise ÷ target riser (rounded up). Stringer length = √(rise² + run²). Comfortable stairs satisfy 2 × riser + tread ≈ 24–25 in.
Related calculators
- Concrete Steps CalculatorHow much concrete do concrete steps need? Enter number of steps, rise, run, width and landing for an exact volume.
- Deck CalculatorFree deck calculator: deck boards, joists at 16 in on center and screws for wood or composite decking.
- Roof Pitch CalculatorConvert rise and run to roof pitch (x/12), angle in degrees, percent slope and area multiplier.
Frequently asked questions
What is the maximum riser height for stairs?
7¾ in under the International Residential Code, with treads at least 10 in deep and no more than ⅜ in variation between steps.
Your business here? Sponsor this calculator from $13/week. See placements
Estimates only. Check quantities with your supplier or contractor before ordering.