From the California State Controller's Office, a paycheck calculation spreadsheet:
If you have Microsoft Excel (Macintosh or PC) or a spreadsheet software application that can read an XLS file, you can download a spreadsheet that will do paycheck calculations. This may be useful to you if you are considering changing your Federal or State tax withholding, deferred compensation, or tax sheltered annuity amounts.
If you are having difficulty viewing the input calculation screen, press and hold the "Ctrl" key then tap the F10 key to "maximize" the viewing screen. For a full screen view of the Excel file double click the title bar area.