Spiral Staircase Calculator

01 Staircase dimensions

Inside diameter (center post / open well)

in

Outside diameter

in

Angle of rotation

°

Total rise (floor to floor)

in

Maximum riser rise (code limit, typ. 9.5 in / 24 cm)

in

Minimum tread depth required (at walk line, code check)

in

02 Plan & elevation

Plan view

Elevation view

03 Steps & rise

Number of steps

—

Number of treads

—

Actual riser rise

—

04 Tread dimensions

Tread angle

—

Tread length (depth)

—

Inner arc

—

Outer arc

—

Tread depth check

—

05 Other results

Handrail length

—

Inner stringer length

—

Inner stair angle

—

Outer stair angle

—

Headroom clearance

—