What are the 401k tax forms? Your W-2 reports what you put in while you work, and Form 1099-R reports money that comes out, with each amount flowing to a specific line on Form 1040.
Key Takeaways
- A pre-tax 401(k) deferral shows in W-2 box 12 with code D and is left out of your box 1 taxable wages (IRS W-2 codes).
- A Roth 401(k) deferral shows in box 12 with code AA and does not reduce box 1, because it is an after-tax designated Roth contribution (IRS).
- Form 1099-R reports distributions and rollovers of $10 or more and is generally furnished to you by January 31 (IRS 1099-R instructions).
- Box 7 code G flags a direct rollover to another eligible plan, which is usually tax-free (IRS).
- 401(k) distributions land on Form 1040 lines 5a and 5b, separate from IRA distributions on lines 4a and 4b (IRS Publication 575).
- Form 5498 reports IRA contributions, not 401(k) activity, and is generally issued by May 31 (IRS Form 5498).
- The 2026 elective deferral limit is $24,500 ($8,000 catch-up at 50+, $11,250 for ages 60 to 63), reported in box 12 (IRS).
401k Tax Forms: The Numbers That Matter
Figures reflect the 2026 tax year. Confirm your own amounts against the actual forms your employer and plan provider issue.
What are the 401k tax forms at a glance?
Two forms do most of the work: the W-2 while you are contributing, and Form 1099-R once money leaves the plan. The W-2 comes from your employer, and the 1099-R comes from the plan administrator or custodian.
A third form, Form 5498, often causes confusion. It is an IRA form, not a 401(k) form, so it appears only if you moved 401(k) money into an IRA. The table below maps each form to what it reports and when it typically arrives.
| Form | What it reports | When it arrives |
|---|---|---|
| W-2 (box 1, box 12, box 13) | Your wages and your 401(k) contributions for the year. Pre-tax deferrals use code D; Roth deferrals use code AA. | By January 31 (from your employer) |
| Form 1099-R | Distributions and rollovers out of the plan, plus the box 7 code that describes the type of payout. | Generally by January 31 (from the plan) |
| Form 1040 (lines 5a and 5b) | Where your 401(k) distribution is entered: gross on 5a, taxable on 5b. | Filed by you at tax time |
| Form 5498 (IRA form) | IRA contributions, rollover contributions and year-end value. Appears only if 401(k) money moved into an IRA. | Generally by May 31 (from the IRA custodian) |
What does your W-2 report about a 401(k)?
Your W-2 shows both your taxable wages and the 401(k) contributions you made through payroll. The mechanics differ sharply between a pre-tax deferral and a Roth deferral, and reading box 1 against box 12 is how you tell them apart.
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A pre-tax 401(k) deferral is excluded from box 1, the federal taxable wages figure, so the money is never counted as current income (IRS Topic 424). That exclusion is why calling a 401(k) contribution a deduction is imprecise; the amount simply never enters box 1. Our explainer on whether 401(k) contributions are tax deductible walks through that distinction in detail.
The deferral is not invisible, though. It still appears in box 12, and it remains part of your Social Security and Medicare wages in boxes 3 and 5, because payroll taxes apply before the deferral is taken out (IRS). Box 13 also has a Retirement plan checkbox that the employer marks. If you want the underlying mechanics, see how a 401(k) works.
Box 12 codes: what do code D and code AA mean?
Box 12 uses letter codes to label each item, and two of them carry your 401(k) contributions. Code D is the pre-tax deferral and code AA is the Roth deferral, and the IRS defines them precisely. The letter in the plan’s own name has its own explanation in why it is called a 401(k).
| Box 12 code | Meaning | Effect on box 1 wages |
|---|---|---|
| D | Elective deferrals to a 401(k) cash-or-deferred arrangement, including a SIMPLE 401(k). | Excluded from box 1 |
| AA | Designated Roth contributions under a 401(k) plan. | Included in box 1 (after-tax) |
| BB | Designated Roth contributions under a 403(b) plan. | Included in box 1 (after-tax) |
| EE | Designated Roth contributions under a governmental 457(b) plan. | Included in box 1 (after-tax) |
These labels come straight from the IRS list of W-2 retirement plan codes. If your plan offers both flavors, choosing between them is the classic Roth 401(k) versus traditional 401(k) decision, and an employer match will show up too; here is what a 401(k) match is and how it is handled.
What is Form 1099-R and when does it arrive?
Form 1099-R reports money paid out of the plan, including ordinary withdrawals, hardship distributions, and rollovers. The plan issues it when a reportable distribution of $10 or more occurs, and it is generally furnished to you by January 31 (IRS instructions for Forms 1099-R and 5498).
The most important boxes are box 1 (gross distribution before withholding), box 2a (taxable amount), box 4 (federal income tax withheld), box 5 (employee or designated Roth contributions), and box 7 (the distribution code). For a deeper walkthrough, our guide to Form 1099-R covers every box. How the taxable amount is figured is the subject of how 401(k) withdrawals are taxed. Contributions are reported separately, as covered in how a W-2 shows 401(k) contributions.
Which box 7 codes matter on Form 1099-R?
Box 7 is where the plan tells the IRS what kind of distribution this was, and the single letter or number changes how the payout is taxed. A handful of codes cover most retirement situations.
| Box 7 code | What it signals |
|---|---|
| 1 | Early distribution, no known exception (generally taken before age 59 1/2). |
| 2 | Early distribution, an exception applies. |
| 7 | Normal distribution (participant is age 59 1/2 or older). |
| G | Direct rollover to an eligible retirement plan, usually not taxable. |
| B | Distribution from a designated Roth account. |
| H | Direct rollover of a designated Roth account to a Roth IRA. |
Code definitions are from the IRS box 7 instructions. A code 1 distribution often signals a possible early-withdrawal penalty, a topic covered in the 401(k) early withdrawal penalty guide.
Where do 401(k) distributions go on Form 1040?
A 401(k) distribution is entered on Form 1040 lines 5a and 5b: the gross amount from box 1 goes on line 5a, and the taxable amount goes on line 5b (IRS Publication 575). This is a distinct pair of lines from IRA distributions, which use lines 4a and 4b.
If the distribution is fully taxable, the instructions let you enter the total on line 5b alone. The distinction between the gross line and the taxable line is what keeps a nontaxable rollover from being taxed by mistake.
How are direct rollovers reported?
A direct rollover is still reported, even though it is usually tax-free. The plan issues a Form 1099-R with code G in box 7, showing the gross amount in box 1 and, for a full pre-tax rollover, $0 in box 2a (IRS).
On the return, you report the gross rollover on line 5a and the taxable amount (often zero) on line 5b, writing the word Rollover next to the line as the instructions direct (IRS Publication 575). The mechanics of moving the money are covered in how to roll over a 401(k) to an IRA, and the reporting steps in how to report a rollover on your taxes.
A Roth conversion is a special rollover that is taxable, so it also generates a 1099-R and is reported differently; see how to report a Roth conversion on taxes. Retirees in a lower-bracket year sometimes model a conversion after they stop working, when the paperwork above is fresh and the taxable line is easier to plan around.
Why does Form 5498 not cover your 401(k)?
Form 5498 reports IRA contribution information, so it never reflects money still sitting inside a 401(k). The IRA custodian files it and sends you a copy, generally by May 31, later than the other forms because it captures prior-year IRA contributions made up to the filing deadline (IRS Form 5498).
You will see a 5498 in the 401(k) world only after a rollover, when the receiving IRA reports the incoming rollover contribution. It is informational, so there is nothing to enter from it on your return. The point to remember is simply that 401(k) contributions live on the W-2, while IRA contributions live on the 5498.
How do 401k tax forms fit retirement tax planning?
Reading these forms correctly is the foundation of any withdrawal or conversion strategy, because every dollar the forms report is a dollar the tax code has an opinion about. The box 7 code, the taxable line, and the timing of each form together define your taxable income for the year.
For households weighing conversions, the same 1099-R and Form 1040 lines that report a routine withdrawal also report a Roth conversion, so understanding the paperwork is a prerequisite, not an afterthought. A fee-only fiduciary such as Q3 Advisors can model whether a conversion fits a given low-bracket year, drawing on the same forms described here.
Plan the paperwork before the payout
Understanding which 401k tax forms report each move makes conversion and withdrawal planning far clearer. Learn more about the Roth conversion process at Q3 Advisors.
Frequently asked questions about 401k tax forms
Do you get a 1099-R for a 401(k) if you only contributed and did not withdraw?
No. Contributions are reported on your W-2 in box 12, not on a 1099-R. Form 1099-R is issued only when a reportable distribution or rollover of $10 or more leaves the plan, generally by January 31 the following year.
What box on the W-2 shows 401(k) contributions?
Box 12. A pre-tax deferral uses code D, and a Roth 401(k) deferral uses code AA. The employer also checks the Retirement plan box in box 13.
Does a pre-tax 401(k) contribution lower the wages in box 1?
Yes. A pre-tax elective deferral (code D) is excluded from box 1 taxable wages, though it still counts in the Social Security and Medicare wage boxes 3 and 5.
What does box 7 code G mean on a 1099-R?
Code G marks a direct rollover to another eligible retirement plan, which is generally tax-free. The gross amount appears in box 1 and, for a full pre-tax rollover, box 2a shows $0.
Where does a 401(k) distribution go on Form 1040?
On lines 5a and 5b. The gross distribution from box 1 of the 1099-R goes on line 5a, and the taxable amount goes on line 5b. IRA distributions use the separate lines 4a and 4b.
Is Form 5498 a 401(k) form?
No. Form 5498 reports IRA contributions and year-end IRA value, and it is issued by the IRA custodian, generally by May 31. It appears in a 401(k) situation only after money is rolled into an IRA.
How is a Roth conversion reported compared to a normal 401(k) rollover?
A Roth conversion is a taxable rollover, so it generates a 1099-R and its taxable amount flows to line 5b, unlike a tax-free direct rollover where the taxable line is often zero. The reporting steps differ, which is why conversions are handled on their own worksheet.
This article is for educational purposes only and is not individualized investment, tax, or legal advice. Consult a qualified professional about your specific situation.
