READING THE STUB
What Each Line on a Pay Stub Actually Is
A pay stub has four blocks, and almost every question about one comes from confusing two of them. Gross pay is everything you earned in the period before anything is removed. Pre-tax deductions — traditional 401(k), health premiums, HSA, FSA — come out next, and they reduce the wage the tax lines are computed on. Taxes are then withheld on what is left. Post-tax deductions such as Roth contributions, union dues, garnishments and most insurance top-ups come out last and change nothing about the tax.
That ordering is why a $200 pre-tax deduction costs you less than $200 of take-home pay and a $200 post-tax deduction costs you exactly $200. It is also why your final stub’s YTD gross will not match Box 1 of your W-2: Box 1 is taxable wages, which is gross minus the pre-tax block.