Pay Stub Decoder

What Do the Codes on My Pay Stub Mean?

Pay stub codes fall into five groups: what you earned, what the government withheld, what came out before tax, what came out after tax, and what is printed for information only. Sort every abbreviation into one of those five buckets and the stub stops being a wall of letters.

There is no national standard for these codes. Each payroll system defines its own, and employers customize them on top of that, which is why university payroll offices publish code lists that apply only to their own staff. The same three letters can mean two different things at two employers: MED is Medicare tax in most payroll systems and the medical premium in a few, and ADD is additional pay on the earnings side but Accidental Death and Dismemberment insurance on the deduction side.

The decoder above labels every code and amount you type in and totals each group. Nothing is uploaded, and it never asks who you work for.

Pre-Tax, Post-Tax, and Why Your Taxes Are Not a Simple Percentage of Gross

Payroll runs in an order, and the order is the reason the arithmetic looks wrong. Pre-tax deductions come out of gross pay first. Tax is calculated on what is left, which is the figure your stub may print as taxable wages or TAXWAGES. Post-tax deductions come out of the remainder. Multiply gross pay by any tax rate and you will miss, because the tax was never charged on gross pay in the first place.

Pre-tax lines lower your taxable wages: traditional 401(k) and 403(b), 457(b), HSA, health care and dependent care FSA, and the health, dental, and vision premiums that run through a Section 125 cafeteria plan. Post-tax lines do not: Roth contributions, union dues, garnishments and child support, most voluntary life insurance, disability premiums taken after tax on purpose, and 401(k) loan repayments.

Roth is the one that catches people out. It sits inside the same retirement plan as the pre-tax 401(k), often on the line directly below it, but it is taken after tax. If you switched your contribution to Roth and your take-home dropped without your gross changing, that is the switch you are looking at. To see what the withholding lines should look like for your situation, try the take-home paycheck calculator.

How to Check Whether Your Stub Adds Up

Four steps, in this order:

1. Check the earnings side against your own record. Confirm the hours behind REG, and confirm that OT, HOL, and SHFT are all present. A missing premium line is the most common real discrepancy, and it is the one nobody catches without their own hours log.
2. Enter every deduction line, including the small ones. A forty cent vision premium is still forty cents of the gap you are trying to explain.
3. Compare the computed net to the printed net. If the difference is a few cents, that is rounding. If it is a round number, you probably skipped a line.
4. Separate the informational lines before you conclude anything. GTL, imputed income, and anything ending in ER never left your check, so they must not be part of the subtraction.

Step one is the step you can control. If you clock in and out with Timeclock44, you have your own hours record to hold the earnings lines against, and a PDF or CSV to attach when you email payroll. When the earnings total and the gross do not match, the overtime calculator and the shift differential calculator will tell you what the missing line should have been worth.

Codes Worth a Second Look

OASDI that stops partway through the year

Social Security tax applies only up to an annual wage base. Once your year-to-date wages pass it, the OASDI line stops for the rest of the year and your take-home rises. Medicare, shown as MED or MEDI, has no cap and keeps coming out of every dollar.

MED meaning two different things

Most payroll systems use MED for Medicare tax. Some employers use it for the medical insurance premium, which is a pre-tax deduction, not a tax. If your MED line is large relative to the other tax lines, it is probably the premium. Enter it as MEDPRE or HEALTH so the pre-tax subtotal is right.

SDI, PFML, and SUI

State disability and paid family leave premiums appear only in the states that run those programs, so a coworker in another state may have no equivalent line. State unemployment is funded entirely by the employer in most states, and only a few withhold a small employee share, so an SUI line on your side of the stub is worth a question.

Garnishment and child support

Garnishment and child support deductions are ordered by a court or an agency, and federal law caps how much of your disposable earnings can be taken. If the amount looks steep, the wage garnishment calculator checks it against the federal limit.

Arrears lines that double up

When a deduction is missed in one period, payroll often catches it up in the next, so you see the same code twice: one current line and one arrears line. Both are real, and both count. The decoder flags duplicate codes rather than assuming one of them is a mistake.

Pay Stub Code Glossary

Sixty codes and their common variants, grouped by what they do to your check. The decoder treats the aliases in the second column as the same code, so type whichever version your employer prints.

Two suffix conventions run across all of these. EE means the employee share, the part withheld from you. ER means the employer share, which is their money and never reduces your take-home, so the decoder reports ER lines separately instead of subtracting them. You may also see PRE or PT for a pre-tax variant, AT for an after-tax variant, and ARR for an arrears catch-up.