Ferrite toroid calculator
Here you can see the formulas that the calculator uses to calculate the inductance. The online calculator uses the wire diameter to determine its length and the possibility of fitting it in the inner diameter of the toroid. The outer diameter of the wire (with insulation) should be using in this calculator. You can download the cross-platform app Coil64 to calculate ferrite toroid inductance coil offline. Here are the Amidon iron powder toroids calculator and the Amidon ferrite toroids calculator.
For correct calculation at radio frequencies, you have to use the real part of the complex magnetic permeability μ' of the ferrite as the relative permeability μr. This value depends on the ferrite material and the frequency. At low frequencies, provided the coil is operating in weak fields, the initial permeability μi value can be used. These parameters can be found in the manufacturer's datasheets.
- The calculator allows calculating only low-current coils, not a power supply chokes, see more...
- You can determine the unknown permeability of the toroid core by the following calculator.
ENTER THE INPUT DATA:
| Select units: | AWG → | SWG → |
| L | = | – Required inductance | |
| OD | – Outer diameter of ring | ||
| ID | – Inner diameter of ring | ||
| h | – Height of ring | ||
| C | – Chamfer | ||
| µr | = | – Relative magnetic permeability | |
| d | – Diameter of wire |
| N | = | – Number of turns |
| AL | = | – inductance factor of the ring [nH/N2] |
| Lw | – Required length of wire* |
*Necessary for winding wire length without the leads.
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