How to correctly calculate social security tax to be withheld

[Archontechnica]

I received a message on TurboTax while doing my that my only employer in 2020 over taxed my social security by $442.63.  When I spoke to my employer about this I was told:

The federal taxable wages differ from the soical secuirty taxable wages in that 401k deferrals are excluded from federal taxable wages but not drom Social Security or Medicare wages.

Can someone clarify who is correct (TurboTax or employer) and the correct way to calculate SS tax?

Thanks!

[DoninGA]

Look at your W-2 and the W-2 you entered in TurboTax.

Box 3 is your Social Security wages.  Box 4 is your Social Security taxes paid.  Are the box 4 taxes paid 6.2% of the box 3 wages?