Your W-2, Box by Box: What Every Number Means (2026 Edition)

The Letter Boxes: Identification

Boxes a through f are just identification — your Social Security number, your employer's EIN, and both addresses. One thing genuinely matters here: check your SSN. A wrong SSN means your wages and withholding get credited to the wrong person at the Social Security Administration, which can quietly shortchange your future benefits. It's the most consequential typo on the form.

Box 1: Federal Taxable Wages

Box 1 is your wages for federal income tax purposes — and for most people it's noticeably smaller than your salary. That's because pre-tax items are already subtracted: traditional 401(k) contributions, health insurance premiums paid through a Section 125 plan, FSA and HSA contributions. If you earned a $70,000 salary and put $8,000 into a traditional 401(k), Box 1 shows $62,000. This is the number your tax return starts from, which is exactly how a 401(k) saves you income tax now.

Box 2: Federal Income Tax Withheld

Box 2 is the total federal income tax your employer sent to the IRS on your behalf during the year. It is not your tax bill — it's a running prepayment based on your W-4. Your actual liability gets computed on your return; if Box 2 is bigger, the difference is your refund, and if it's smaller, you owe. A large refund isn't a bonus — it means your W-4 had too much withheld all year. A large bill means the opposite. Either way, the fix is a new W-4, and the paycheck calculator can show you what withholding should look like for your situation.

Boxes 3–6: Social Security and Medicare

• Box 3 — Social Security wages. The wages subject to the 6.2% Social Security tax, capped at the 2026 wage base of $184,500. Earn more, and Box 3 stops there anyway.
• Box 4 — Social Security tax withheld. Should be exactly 6.2% of Box 3, maxing out at $11,439 for 2026 (6.2% × $184,500). If you had multiple employers and your combined Box 4 amounts exceed $11,439, the excess comes back as a refundable credit on your return — see our post on the Social Security wage base for how that works.
• Box 5 — Medicare wages. Like Box 3 but with no cap. Medicare's 1.45% applies to every dollar.
• Box 6 — Medicare tax withheld. 1.45% of Box 5, plus the 0.9% Additional Medicare Tax your employer withholds on wages over $200,000 (the annual thresholds on your return are $200,000 single / $250,000 married filing jointly).

Why Box 1 ≠ Box 3 ≠ Box 5

Three different definitions of "wages" live on one form, and the differences are where most W-2 confusion comes from:

• Traditional 401(k) contributions reduce Box 1 only. They're exempt from income tax but not from FICA — you pay Social Security and Medicare on them in full. That $70,000 earner with $8,000 in the 401(k) shows Box 1 = $62,000 but Box 3 = $70,000 and Box 5 = $70,000.
• Section 125 items reduce all three. Health premiums, FSA, and HSA contributions through payroll escape both income tax and FICA, so they lower Boxes 1, 3, and 5 together.
• The cap splits Boxes 3 and 5 for high earners. Someone with $210,000 in wages and no pre-tax deductions shows Box 3 = $184,500 (capped) but Box 5 = $210,000 (uncapped). Their Box 4 is the $11,439 maximum, while Box 6 is 1.45% × $210,000 = $3,045 plus 0.9% on the $10,000 over $200,000 ($90) — $3,135.

So a quick self-check: Box 1 below Boxes 3 and 5 usually means retirement contributions. All three equal means no pre-tax benefits. Box 3 below Box 5 means you passed the wage cap. None of these are errors — they're the design.

Boxes 7–11: The Ones Most People Skip

Box 7 (tip income reported to your employer) and Box 8 (tips your employer allocated to you) matter mainly in food service. Box 10 shows dependent care benefits, such as a dependent care FSA — it feeds into Form 2441 at filing time. Box 11 reports distributions from nonqualified deferred compensation plans, mostly an executive-comp item. Box 9 is permanently grayed out — a retired verification program. If these are blank, that's normal.

Box 12: The Codes Worth Knowing

Box 12 is a catch-all where letter codes label special items. There are dozens; four are worth recognizing on sight:

• Code D — traditional 401(k) contributions. This is the paper trail for why your Box 1 is smaller than your salary.
• Code W — HSA contributions through your employer. Includes both employer money and your payroll contributions; it flows to Form 8889 so the IRS can confirm you stayed under the HSA limit.
• Code DD — employer-sponsored health coverage cost. Often the biggest shock on the form: the total your employer paid for your health coverage. It's informational only — not income, not taxed, not deductible. It exists so you can see what your insurance actually costs.
• Code TT — qualified overtime premium (new). Starting with 2026 W-2s, employers report the overtime premium you earned — the extra "half" in time-and-a-half — under this new code. It's the number that unlocks the overtime deduction created by the 2025 tax law: a deduction of up to $12,500 (single) or $25,000 (married filing jointly) for the premium portion of overtime, phasing out above $150,000/$300,000 of income, for tax years 2025–2028. FICA still applies to every overtime dollar, and the deduction is only for W-2 employees. Our full guide to the 2026 overtime tax deduction covers who qualifies and how much it's actually worth.

Boxes 13 and 14: The Oddities

Box 13 has three checkboxes. "Retirement plan" is the one that bites: if it's checked, you were an active participant in a workplace plan, which can limit how much of a traditional IRA contribution you're allowed to deduct. "Statutory employee" flags a rare hybrid worker status (certain drivers and salespeople) whose wages go on Schedule C. "Third-party sick pay" appears if a disability insurer paid you during the year.

Box 14 is the junk drawer — employers can put almost anything here with any label they like: state disability insurance, union dues, tuition assistance, charitable payroll deductions, vehicle allowances. If a Box 14 entry is cryptic, ask payroll what it means; some entries (like certain state-level taxes) are deductible on your return, and tax software will ask.

Below all this, Boxes 15–20 repeat the same story for state and local tax: state wages and withholding, then local wages and withholding with the locality's name in Box 20.

What to Do If Your W-2 Looks Wrong

Run three quick checks the day it arrives: your SSN is correct, Box 4 equals 6.2% of Box 3, and Box 6 is at least 1.45% of Box 5. Then sanity-check Box 1 against your final December pay stub's year-to-date taxable wages — they should match.

1. Contact payroll first. Most errors are clerical, and the fix is a corrected form called a W-2c. Don't file your return with numbers you know are wrong.
2. If your employer won't fix it (or has vanished), call the IRS after the end of February. They'll contact the employer, and if that fails you can file using Form 4852, a substitute W-2 built from your own pay stubs.
3. If a W-2c arrives after you've already filed with materially different numbers, you may need to amend your return with Form 1040-X.

Predict next January's W-2 today: The Pay-Breakdown paycheck calculator shows how your salary, 401(k) contributions, and withholding translate into full-year numbers — so you can spot a withholding problem in August instead of discovering it on a W-2 in January.