Those of us who do circuit design are constantly having to design common voltage dividers. Simple ones are, well... simple... usually. Add a pot or a rheostat, and/or more than 2 resistors, and you can go bananas trying to get the voltages you need. Why is this so hard sometimes? Because it's rare that the values that come up on your calculator match the values that you can buy. So, you choose the nearest standard value and recalculate using that value. If you're not satisfied with the error you try again... and again. Not only that but who keeps the formula(s) for a 3-element voltage divider handy? This program does it all for you, in addition providing you with worst case results based on resistor tolerances you have chosen. | 
