How to Read Your W-2: Boxes, Codes, and What's Taxable vs. Nontaxable

Educational guide — understanding the form that summarizes your year as an employee

If you filled out a Form W-4 when you started your job, your Form W-2 is what comes back the following January — a summary of everything you were paid and everything withheld during the year. Most people glance at Box 1 and move on, but the rest of the form actually tells a more complete story, and a few boxes commonly get misunderstood.

The Main Wage Boxes (1, 3, 5) — Why They're Different Numbers

A lot of people assume Box 1, Box 3, and Box 5 should all show the same number. They often don't, and that's normal:

• Box 1 — Wages, tips, other compensation. This is your taxable income for federal income tax purposes. It's typically lower than your gross pay because pre-tax deductions (like traditional 401(k) contributions or health insurance premiums) are subtracted before this number is calculated.
• Box 3 — Social Security wages. This is the wage base used for Social Security tax, and it excludes some pre-tax deductions differently than Box 1 does. It's also capped each year at the Social Security wage base — earnings above that cap aren't subject to Social Security tax at all.
• Box 5 — Medicare wages. Similar to Box 3, but for Medicare tax — and unlike Social Security, there's no wage cap on Medicare tax, so this number can be the highest of the three for higher earners.

Seeing three different numbers isn't an error — it reflects that different pre-tax benefits are excluded from different tax bases.

Box 12: The Codes That Confuse Everyone

Box 12 reports special items using single or double letter codes, each with its own tax treatment. A few of the most common:

• Code D — Pre-tax contributions to a traditional 401(k). This amount is already excluded from Box 1, so it isn't taxed now (it's taxed later, when you withdraw it in retirement).
• Code AA, BB, EE — Designated Roth contributions (Roth 401(k), Roth 403(b), Roth governmental 457(b)). These are after-tax contributions, so unlike Code D, this amount is still included in Box 1 — you're paying tax on it now, in exchange for tax-free withdrawals later.
• Code W — Employer and employee contributions to a Health Savings Account (HSA). Generally not included in taxable wages, within annual HSA contribution limits.
• Code DD — The total cost of employer-sponsored health coverage. This is informational only — it does not mean that amount is taxable. Employer-paid health insurance premiums are generally excluded from taxable wages entirely.
• Code C — The taxable cost of group-term life insurance coverage above $50,000. Unlike basic employer-provided life insurance up to $50,000 (which is tax-free), coverage above that threshold has a taxable component, shown here and included in Box 1.
• Code P — Certain excludable moving expense reimbursements (now limited mostly to active-duty military moves under current law).
• Code Q — Nontaxable combat pay (military).

There's a longer list of codes in the IRS's General Instructions for Forms W-2 and W-3 — these are simply the ones that show up most often.

Other Boxes Worth Knowing

• Box 10 — Dependent care benefits. Amounts your employer paid or set aside for dependent care (like a Dependent Care FSA). Up to the annual exclusion limit, this is nontaxable; if you receive more than the limit, the excess gets added back into Box 1.
• Box 13 checkboxes — flags for things like "Retirement plan" (if you're covered by a workplace retirement plan, which can affect IRA deduction rules) or "Third-party sick pay."

The Bigger Question: What's Taxable and What Isn't?

A lot of confusion comes from assuming "if it's on my W-2, it must be taxed." That's not quite right — plenty of amounts appear on a W-2 for informational or reporting purposes without being included in your taxable wages (Box 1). Some common examples of things that are generally nontaxable, even though they may show up somewhere on your W-2:

• Pre-tax retirement contributions (Code D and similar) — excluded from Box 1 now, taxed later on withdrawal
• Employer-paid health insurance premiums — generally fully excluded from taxable wages
• HSA employer contributions (Code W) — generally excluded, within annual limits
• Dependent care assistance (Box 10) — nontaxable up to the annual limit
• Combat pay (Code Q) — nontaxable for military service members
• Certain educational assistance — employer-provided tuition or student loan payment assistance can be excluded from wages up to an annual limit under current law
• Group-term life insurance up to $50,000 — the first $50,000 of coverage is tax-free; only amounts above that show up as taxable (Code C)

By contrast, things like your regular salary, bonuses, most fringe benefits beyond specific excludable categories, and Roth retirement contributions are generally fully included in your taxable wages.

A Practical Way to Check Your Own W-2

When your W-2 arrives, it can help to compare Box 1, 3, and 5 side by side, then check Box 12 for any codes you don't recognize. If a number looks off — for example, Box 1 is much lower than you expected — it's often explained by pre-tax benefits you elected during the year (retirement contributions, health insurance, HSA, dependent care), not a mistake on the form.