Spiral Length Calculator

Your details

Archimedean: a flat coil where the winding gap equals the material thickness. Helical: a coil wrapped around a cylinder, like a spring or spiral staircase.
All dimensions must be in the same unit. The result is returned in the same unit.
The total outside diameter of the roll or coil.
mm
The diameter of the inner core or hub.
mm
The thickness of one layer of the wound material.
mm
Spiral length (L)
301,592.895mm

Total arc length of the spiral or helix

Number of turns (N)800
Mean circumference376.991mm
Pitch / radial step per turn0.1mm
Total length301,592.895
Mean circumference376.991

This roll is 301592.9 mm long across 800.0 turns.

  • The roll contains 800.0 turns with a mean circumference of 376.99 mm per turn.
  • Total length is 301.59 m (301592.89 mm).
  • The formula L = pi x N x (D + d) / 2 uses the mean diameter; it differs from the exact arc-length integral by less than 0.1 % for tightly wound coils.

Next stepTo find how much material remains on a partial roll, measure the current outer diameter and recompute.

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