Hi Milpost,
If this an actual payroll you are talking about, then the very
fact that you are asking this question means that you shouldn't
be attempting to do this yourself.
In most countries, if not all, there are many variables to take
into account when calculating tax withholdings and if you
get it wrong you may be criminally liable.
Much better to get an accountant to set up the sheet for
you and then have them review it on a yearly basis or
whenever there are changes to the tax laws.
HTH
Martin