Calculadora de Escada Espiral
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
degraus = ceil(h×100/19); voltas = degraus/13
About this calculator
This calculator designs spiral stairs based on total height (floor-to-floor plus slab). It divides the height by 19 cm (ideal riser) to get the number of steps, rounding up. Then it calculates how many full turns the staircase will have, considering 13 steps per turn. The result shows total steps and required turns.
Use this tool early in architectural design to check if a spiral staircase fits the available space. For example, with a floor height of 2.80 m and a 20 cm slab, total height is 3.00 m. The calculator indicates 16 steps and approximately 1.23 turns. These numbers help define diameter and position.
Important considerations: the 19 cm riser is a reference but may vary per local codes (usually 16-18 cm). Check your building code. Also, spiral stairs have narrower steps at the center; ensure a minimum tread width of 25 cm. This calculator does not replace a professional engineer or architect.
For stairs with more than 15 steps, consider an intermediate landing or change the rotation angle. The formula assumes 13 steps per 360° turn, but you can adjust manually. Remember that comfort and safety depend on detailed design, including handrails and guardrails.
Frequently asked questions
How many steps are needed for a 3-meter height?
For 3 meters, the calculator divides 300 cm by 19 cm, resulting in 15.79, rounded up to 16 steps.
Can I use an 18 cm riser instead of 19 cm?
Yes, but the calculator uses 19 cm as default. You can manually adjust the number of steps by changing the total height in the calculation.
How do I find the diameter of the spiral staircase?
The diameter depends on the tread width. With 13 steps per turn, the angle between steps is 27.7°. The calculator does not provide the diameter, but you can compute it from the desired width.
Does the calculator include a landing?
No. Landings are not included. For stairs with many steps, it is recommended to manually add a landing in the design.