Hexacolor is a Freeware application which helps you to decide which colors to use when you're designing a website or specifing colors which will be viewed on screen.

Using Hexacolor you can mix your desired color using RGB 0-255 or RGB percentages [like the ones used in QuarkXPress®] and you can easily convert RGB 0-255 values to RGB percentage values or vice versa, just by clicking the % tick box