So do I reduce the payroll tax by 50% if entering the gross W2 payroll on form 1120S?

For what reason or function or provision?

By the way, the Title is used for topic Title. Then, you put your content in the input panel, and it will not be limited as to # of  characters.

I'm eagerly waiting to hear why we want to do that 50% reduction.  But I did bring some popcorn, just in case it takes awhile for that answer.

If you are asking if you should only deduct 50% of the Social Security and Medicare taxes that were reported on the 941s, yes (you only deduct the employer portion, because the employee portion is already a deduction included in their gross W-2 wages).

As for how to enter it - only enter the proper amount.

Maybe "payroll math" is helpful:

Gross Payroll = gross wages + employer taxes

But Banking =

Takehome pay + employer taxes + employee taxes + any deductions from the employee (Child support, Health, etc)

That's why All of the employer tax is expense and reported, but the Employee taxes, withholding, garnishment, etc, that is deducted from the Gross Wages is not also Employer expense. The employer already has it as part of Gross Wages. They just didn't give all of those wages to the employee. They held back the tax parts and sent it in for the employee.