Java Toroid Design Applet
Courtesy of Jack Ponton, GM0RWU 
This applet designs a toroid coil. Handbook data for the most usual sizes and material combinations have been included. Less common combinations estimate AL from permeability. Some materials are not available in larger core sizes.

Enter the required inductance in the green box; you must press "enter" at the end of the number. Then select size and material.