Work out the number of steps, riser height, run and stringer length for a staircase.
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How do you calculate stairs for a staircase?
Steps = round(total rise ÷ target riser), riser height = total rise ÷ steps, and stringer = √(rise² + run²). Even risers are essential for safety. For example, a 112-inch total rise with a 7-inch target gives 16 steps of exactly 7 inches each. Many codes cap risers near 7.75 inches — always check local rules.
Understanding your result
Even risers are essential for safety. Many codes limit risers to about 7.75 inches and require treads of at least 10 inches — always check local rules.
Formula and method
Steps = round(total rise ÷ target riser). Riser height = total rise ÷ steps. Stringer = √(rise² + run²).
Worked example
A 112-inch total rise with a 7-inch target gives 16 steps of exactly 7 inches each.
How to use this tool
- Enter the total rise (floor to floor).
- Set a target riser height and tread depth.
- Press Calculate.
About the Stair Calculator
The Stair Calculator turns a total floor-to-floor rise into a step count with even riser heights, the total run and the stringer length you’ll need to cut.
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Frequently asked questions
What is a comfortable stair angle?
Roughly 30–37°, which a ~7-inch riser with a ~11-inch tread produces. Steeper stairs are harder and less safe.