Spiderweb (loading) coil calculator

This tool calculates the inductance, AC loss resistance, quality factor and wire length of a close wound single layer spiderweb coil.
Following limitations apply:

  • "Magnet wire" (solid round copper wire with thin isolation) is used.
  • The coil former has no magnetic loss (eg. PVC, PTFE, PE, porcelain, fiberglass, ...).
  • The coil form thickness (D) must be small in regard with the inner diameter (ID).
Coil dimensions:
Coil form inner diameter (ID):   cm
Coil form thickness (D):   mm
Number of turns (N):   
Wire diameter (d):    mm
Operating frequency (F):    kHz


Inductance :   ... μH
RAC at operating frequency:   ... Ω
Quality factor at operating frequency:   ...
Coil outer diameter (OD):   ... cm
Wire length:   ... m (without leads)