Toroid Coil Winding Calculator

             toroid cores 

Use this online tool to calculate the number of winding turns required to achieve the desired inductance with ferrite and iron powder toroidal cores.

To use the calculator:
First, select the core material type.
     Select Iron Powder for cores with a 'T' prefix (such as the T-50-2).
     Select Ferrite for cores with an 'FT' prefix (such as the FT-43-63).

Material Type:


Core Size

Material Number





For more information about using this calculator, see Using the Toroid Winding Calculator.

For a brief description of toroid core terms used on this page (such as AL and u), see Toroid Coil Terminology.

Two great references on toroidal inductors and transformers:
The ARRL Handbook for Radio Communications 2017

Transmission Line Transformers, 4th Edition, by Jerry Sevick