Skin Depth Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

Share Print Save

A skin depth result can look convincing even when one unit or assumption is off. Electrical and magnetic results can shift sharply with geometry, frequency, phase, material properties, and whether the quantity is a magnitude or signed value. This page keeps the calculation narrow enough to trace the answer back to the values you enter.

What this calculator does

The Skin Depth Calculator connects Resistivity (ρ), Relative permeability (μᵣ), Frequency (f) to the page’s skin depth. Supporting values are included only when they follow from the same relationship, so you can compare the headline with the quantities behind it.

How to use it

Enter Resistivity (ρ), Relative permeability (μᵣ), Frequency (f) using the units shown beside each field. Set Material to match the solve path you want. Keep all values from the same physical case, then check the headline result and any supporting values before changing one input at a time for comparison.

How the calculation works

Skin depth is δ = √[ρ/(πfμ0μr)]. It decreases as frequency or permeability rises and increases with resistivity.

Example

With the default setup (Material = Copper; Resistivity (ρ) = 1.68e-08 Ω·m; Relative permeability (μᵣ) = 1; Frequency (f) = 1e+06 Hz), the page reports skin depth of 0.000065 m. This is a useful baseline: change one input and confirm the new value follows the proportionality in the formula.

How to interpret the result

Read the skin depth with its sign, magnitude, phase, frequency, geometry, and unit as applicable. A field, reactance, power factor, loss, or flux value should be compared only with a quantity defined in the same way.

Limitations and notes

Real electrical and magnetic systems can add parasitics, finite geometry, temperature dependence, nonlinear materials, frequency-dependent losses, tolerances, and measurement uncertainty beyond the ideal relationship shown here. Recheck Resistivity (ρ), Relative permeability (μᵣ) first if the result looks surprising, because an incorrect unit or definition there can dominate rounding error. Safety-critical or standards-based work still needs the applicable design rules and independent verification.