Enter coil parameters, then click Calculate Length.

The spiral coil calculator determines the geometric parameters of a spiral or coiled material (roll). It is based on the Archimedean spiral approximation, where the average diameter is used to estimate the total length. The key parameters are: outer diameter (D), inner diameter (d), material thickness (t), number of turns (n), and total length (L). The relationship is L ≈ π · (D + d) / 2 · n. This is useful for calculating the length of material in a roll (paper, film, wire), designing spiral coils for electronics, or estimating consumption of rolled materials. The calculator can find the length from the other parameters, or the number of turns from the length. The results are approximate due to the assumptions of constant pitch and ideal spiral geometry.

1. Enter the Outer Diameter and Inner Diameter in millimeters.
2. Enter the Material Thickness (pitch per turn) in millimeters.
3. Enter the Number of Turns to calculate length.
4. Alternatively, enter length in the Turns field and click Find Turns.
5. Click Calculate Length to compute the total coil length.
6. The result shows length in mm and m, with the formula used.
7. Click Reset to restore default example values.