The total social security tax is 12.4%. The employer withholds your half 6.2% from your wages and enters that amount in box 4. That has not been deferred usually.
The employer pays the other half 6.2%. The employer is allowed to defer their half.
BUT... if you find that the box 4 amount is less than 6.2%
Under the IRS guidance issued in August 2020, employers were allowed to defer withholding employees' share of Social Security taxes from Sept. 1, 2020 through Dec. 31, 2020. Originally, employers were required to increase withholding and pay the deferred amounts ratably from wages and compensation paid between Jan. 1, 2021 and April 31, 2021, and beginning on May 1, 2021, penalties and interest on deferred unpaid tax liability would begin to accrue.
However, the Consolidated Appropriations Act that President Trump signed at the end of 2020 extended the repayment period through Dec. 31, 2021. Now, penalties and interest on deferred unpaid tax liability will not begin to accrue until Jan. 1, 2022.
