While The Budget Calculator offers a “Free Budget Calculator to get control of your spending and start planning for the future today”, it gave me an excuse to play with Bootstrap 3 with a focus on aligning inputs responsively. Specifically the Grid System employed by Bootstrap provides greater stability/flexibility versus traditional percentage based responsive site design. As far as dealing with inputs, there are a lot of styling options which I encourage others to evaluate first before pursuing your own customizations. Per the core Bootstrap CSS, I kept it intact and used a second file for non-Bootstrap customizations.
Bootstrap can be found at: http://getbootstrap.com
The Budget Calculator can be found at: http://www.thebudgetcalculator.com