Calculates the dimensions of a spiral staircase, including the number of treads, tread width, and overall diameter.
Start with your values, or try a preset.
Enter Floor-to-Floor Height, Desired Tread Width, Number of Treads (including the top landing), and Central Column Diameter in the units shown.
Read Effective Tread Width, Tread Angle (degrees), Staircase Diameter, and Tread Height in the results panel. Results update as you change the inputs.
Choose a preset to load an example, then adjust the values for your situation.
See the inputs and their calculated results.
Floor-to-Floor Height: 270 cm; Desired Tread Width: 80 cm; Number of Treads (including the top landing): 12; Central Column Diameter: 15 cm
Effective Tread Width: 72.5 cm; Tread Angle (degrees): 32.72727273 degrees; Staircase Diameter: 175 cm; Tread Height: 24.54545455 cm
Floor-to-Floor Height: 300 cm; Desired Tread Width: 90 cm; Number of Treads (including the top landing): 14; Central Column Diameter: 20 cm
Effective Tread Width: 80 cm; Tread Angle (degrees): 27.69230769 degrees; Staircase Diameter: 200 cm; Tread Height: 23.07692308 cm
Floor-to-Floor Height: 330 cm; Desired Tread Width: 100 cm; Number of Treads (including the top landing): 16; Central Column Diameter: 25 cm
Effective Tread Width: 87.5 cm; Tread Angle (degrees): 24 degrees; Staircase Diameter: 225 cm; Tread Height: 22 cm
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