And as for the prior answer above, line 18d is the wrong line for 2020. That was the line for 2019. It changed to line 31 in 2020 and 2021.
For 2021 the max for Social Security is $8,853.60 on $142,800 of wages.
For 2021 it will be on Schedule 3 line 11 which goes to 1040 line 31.
