Worked reconciliation
Most explanations of this stop at "a stub is per paycheck, a W-2 is annual". True, and not the thing anyone is actually confused about. The real question is why the W-2 shows a number that matches neither your salary nor your final pay stub — and why two boxes on the same form disagree with each other.
Pay stub
Issued every payday by your employer. Shows one period plus year-to-date running totals. Used to prove current income to landlords and lenders. Not filed with anyone.
W-2
Issued once, by 31 January, for the previous year. Shows taxable wages and withholding. Also filed with the IRS and the SSA, which is why your return has to agree with it.
Take someone earning $75,000, paying $3,600 a year in pre-tax health premiums and contributing $6,000 to a traditional 401(k). Here is what each document reports:
| Figure | Amount | What was removed |
|---|---|---|
| Salary / final stub YTD gross | $75,000 | Nothing — this is gross pay |
| W-2 Box 1 — federal taxable wages | $65,400 | Health premiums and 401(k) |
| W-2 Box 3 — Social Security wages | $71,400 | Health premiums only |
| W-2 Box 5 — Medicare wages | $71,400 | Health premiums only |
Four different numbers, all correct. The rule underneath them is simple once stated: pre-tax insurance comes out of every wage box; a traditional 401(k) comes out of the federal box only. Your retirement deferral escapes income tax but never escapes Social Security and Medicare.
Box 3 − Box 1 should equal your 401(k) contribution
In the example above: $71,400 − $65,400 = $6,000, exactly the amount deferred. Run the same subtraction on your own W-2 and compare it to the 401(k) total on your final pay stub. If they match, the two boxes are consistent. If they do not, something is worth asking payroll about — most often a Roth contribution recorded as traditional, or a deferral applied to the wrong box.
If you contribute to a Roth 401(k) instead, the subtraction gives zero: Roth money is taxed on the way in, so it never reduces Box 1. Seeing zero when you expected your contribution is the fastest way to discover your deferral is going somewhere other than you assumed.
| Situation | Use |
|---|---|
| Filing your tax return | W-2 — the IRS already has a copy |
| Renting an apartment | Recent pay stubs; the W-2 may be requested as backup |
| Mortgage application | Both — stubs for current income, W-2s for history |
| Checking your current withholding | Pay stub, because it reflects today |
| Confirming annual income | W-2 |
| Disputing pay for one period | The stub for that period |
Check this period's stub first
A W-2 is only the sum of the year's stubs. Our checker verifies the FICA rates, overtime and net pay on the stub in front of you.
Open Paycheck Checker →The figures are arithmetic on stated assumptions — a single employer, one full year of employment, pre-tax Section 125 health premiums, and a traditional 401(k) deferral — not a real W-2. Real forms carry state boxes, dependent care benefits, HSA contributions coded in Box 12, and other items that shift the totals. This shows the mechanism, not your specific return. Our methodology page sets out what we model and what we do not.
What is the difference between a pay stub and a W-2?
A pay stub covers one pay period and is issued by your employer every payday. A W-2 is an annual summary of taxable wages and withholding, issued once after year end and also filed with the IRS. You file taxes from the W-2, not from stubs.
Why does my W-2 show less than my salary?
Because Box 1 is wages after pre-tax deductions, not gross pay. On a $75,000 salary with $3,600 of pre-tax health premiums and a $6,000 traditional 401(k) contribution, Box 1 reads $65,400. Nothing is missing — those deductions came out before the wage was taxable.
Why are Box 1 and Box 3 different on my W-2?
Because a traditional 401(k) reduces income-tax wages but not Social Security wages. Box 3 minus Box 1 should equal your 401(k) contribution for the year almost exactly — in our example $71,400 − $65,400 = $6,000. It is a quick way to check your own W-2.
Can I file my taxes with a pay stub?
You should not. Your final stub is a reasonable estimate, but it will not match Box 1 once pre-tax deductions and any imputed income are applied, and the IRS receives the W-2 directly. Filing from a stub is a common cause of a mismatch notice.
What if my W-2 is wrong?
Ask your employer for a corrected W-2 (Form W-2c) and show the figures you believe are right. Comparing against your final pay stub of the year is the usual way to spot it. If the employer will not correct it, the IRS has a process for reporting the discrepancy.
What if I never received a W-2?
Employers must furnish it by the end of January. If it has not arrived, check the address on file and any payroll portal first, then ask the employer. Your final December pay stub is useful evidence of what should be on it.
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