In creating your website it can be very useful to know the hexadecimal values of your RGB colors and vice versa. For instance if you need to match a graphics color to your background all you'd need to do is find out the RGB value of the graphic in your graphics program and convert it to Hexadecimal. On the other hand if you already have a page designed and you'd like to make a header graphic for your site you could take the Hexadecimal background color and convert it to RGB for use in your graphics program.