Skin Depth Calculator

Your details

Selects the resistivity and relative permeability for a common metal. Choose "Custom" to enter your own values.
Electrical resistivity in ohm-metres at room temperature. Auto-filled from the material preset.
Ohm-m
Relative magnetic permeability (mu_r). Non-magnetic metals are close to 1; ferromagnetic metals like iron can be thousands.
AC signal frequency. Switch the unit selector to Hz, kHz, MHz or GHz for convenience.
Hz
Skin depthAudio / RF range
8.4217

Depth at which current density is 1/e (~37 %) of the surface value

Result unitmm
Skin depth (mm)8.421713mm
Skin depth (um)8,421.7133um
Current density at depth36.79%
Min. conductor thickness for 99 % conduction42.1086
Thickness unitmm
8.421713 mm
mm-wave / optical<0.001Microwave0.001-0.1RF / audio0.1-2Power frequency2+

Skin depth in Copper: 8.4217 mm

  • The skin depth is 8.4217 mm, meaning current density falls to about 37 % of its surface value at that depth in Copper.
  • The skin depth is several millimetres, so standard solid conductors are efficient at this frequency. Skin effect losses become significant only at higher frequencies.
  • A conductor thicker than 5 skin depths carries over 99 % of the current - extra thickness beyond that adds weight and cost without reducing AC resistance.

Next stepPair the skin depth with the conductor cross-section to estimate AC resistance, or use it to size a plating layer for an RF component.

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