There are two modes to use this, press M to switch between them: Mode 1: Use bands slider or space bar to change the number of bands. Use 1, 2, 3, 4, and 5 keys on the keyboard to set the colours of the respective bands. Click Calculate and it will show the resistance and tolerance of the resistor. Mode 2: Press Calculate and enter the value of the resistor you want. Default value is ohms, add K for Kilohms or M for Megohms, e.g 2.2K or 5.25M. Then the resistor on-screen will show the coloured bands that you should need to find. It will automatically adjust for 4 or 5 band resistors, and the default tolerance is 5%.
As usual, there is an easter egg (at Christmas?!?!?) Once you find it, do not reset immediately ;) NOTE: The darker grey is grey, the lighter grey is silver UPDATE- 12/11/18: Added colour calculation from resistance!