Pay stub deduction codes are abbreviations and codes used to represent different types of deductions on a pay stub. Here are some common examples: State, SIT, or SWT for state income tax withholding, FICA for Medicare and Social Security taxes, FED, FIT, or FWT for federal income tax withholding, INS for insurance deductions (e.g., life insurance), YTD for year-to-date calculations, MED for health, vision, or dental insurance deductions, and FSA or HSA for contributions to flexible spending accounts (FSA) or health savings accounts (HSA). Additionally, 401(k) or RET may represent contributions made into a retirement plan.