What this calculator does
Skin Depth works out depth below a conductor surface where AC current density falls to 1/e of its surface value. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
Formulaδ = √(ρ / (π·f·μ0·μr)), μ0 = 4π×10⁻⁷ H/m
The inputs explained
| Field | What to enter |
|---|---|
| Resistivity (ρ) (Ω·m) | A number, measured in Ω·m. Starts at 1.68e-8. |
| Frequency (f) (Hz) | A number, measured in Hz. Starts at 60. |
| Relative permeability (μr) | A number. Starts at 1. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with resistivity (ρ)
Every other input is held at the calculator’s starting values while resistivity (ρ) varies. Select any row to load that scenario into the calculator.