Stair Calculator

Total Height (Floor-to-Floor)

Rise Height per Step

Tread Depth

Number of Steps

steps

Total Run Length

Stair Angle

degrees

To calculate staircase:

Divide the total height (floor-to-floor) by the desired rise height per step to get the number of steps.
Multiply the number of steps by the tread depth to determine the total run length.
Use trigonometry:
- Angle = arctan (rise height ÷ tread depth)
- This gives the angle of the stairs.

You need a staircase for a floor-to-floor height of 120 inches with a rise height of 7 inches and a tread depth of 10 inches.

Number of Steps:
$120 \div 7 = 17.14$ , rounded to 18 steps.
Run Length:
$18 \times 10 = 180 \, \text{inches (15 feet)}$ inches (15 feet).
Stair Angle:
$\text{arctan} (7 \div 10) = 34.99^\circ$ .

This ensures your stairs are safe, functional, and meet building codes.