Free Stair Calculator

Find the number of steps, riser height, and tread depth for your staircase.

Most building codes require riser heights between 7-7.75 inches for residential stairs, with a common comfort rule being 2× riser + tread ≈ 25 inches. This calculator finds the closest even riser height that divides your total rise evenly across whole steps.

Worked Example

Example: Total rise of 108 inches with a target 7.5in riser → 14 steps at exactly 7.71in riser height each, with a recommended 10.6in tread depth.

Formula / Method

Number of Steps = round(Total Rise / Target Riser)
Actual Riser = Total Rise / Number of Steps
Tread Depth ≈ 25 − 2 × Actual Riser (comfort rule)

Worked Example

Example: Total rise of 108 inches with a target 7.5in riser → 14 steps at exactly 7.71in riser height each, with a recommended 10.6in tread depth.

Formula / Method

Number of Steps = round(Total Rise / Target Riser)
Actual Riser = Total Rise / Number of Steps
Tread Depth ≈ 25 − 2 × Actual Riser (comfort rule)