Tax documents decoded: W-2, 1099-NEC, 1099-K, 1099-B, 5498

Tax forms arrive like exam papers written in a language you never studied. The trick: every form is just a copy of something already sent to the IRS. Your job isn't to understand every box — it's to make sure your return includes everything the IRS already knows about, because their computers match forms to returns automatically, and mismatches generate letters.

W-2: your job, summarized

• Box 1: taxable wages — often LESS than your salary because pre-tax 401(k) and health premiums were subtracted. This is the number your tax is based on.
• Box 2: federal income tax already withheld — your prepayments.
• Boxes 3–6: Social Security and Medicare wages and taxes. Box 3 can differ from Box 1 (401(k) contributions are still FICA-taxed).
• Box 12: coded extras — D is your 401(k) contributions, W is HSA contributions (yours plus employer's), DD is the cost of your health coverage (informational, not taxed).
• Employers must send it by January 31. Multiple jobs = multiple W-2s, and every one goes on the return.

The 1099 family: money from anyone who isn't your employer

1099s report income with no taxes withheld — which means the tax is your problem. The most common members: 1099-NEC (freelance and contractor pay of $600+), 1099-K (payment apps and marketplaces), 1099-B (investment sales), 1099-INT/DIV (bank interest and fund dividends), 1099-R (retirement account distributions), 1099-G (unemployment and state refunds), SSA-1099 (Social Security).

1099-K: the payment-app form that scares people unnecessarily

The 1099-K reports gross payments processed through platforms like PayPal, Venmo (business), Etsy, eBay, and Stripe. Reporting thresholds have bounced around with legislation, so you may receive one for fairly modest activity. Two calming facts: personal transfers between friends and family were never supposed to be included, and selling your own used stuff at a loss (the usual garage-sale situation) creates no taxable income — but once a 1099-K exists, you should report it and back the nontaxable portion out on the return rather than ignore it.

1099-B: the one where the broker's numbers can be wrong

5498: the form that arrives late on purpose

Form 5498 reports your IRA contributions, rollovers, conversions, and year-end balance. It arrives around May — after the filing deadline — because IRA contributions for a tax year can be made until April 15. You don't file it or wait for it; it's confirmation paperwork. But KEEP it: 5498s are your permanent proof of Roth basis and of nondeductible contributions (backdoor Roth documentation), which you may need to show decades from now.

A January system that prevents April panic

1. Make a checklist of expected forms before they arrive: one W-2 per job, a 1099 per bank/brokerage/platform/client, 1098 if you have a mortgage, 1099-SA if you spent HSA money.
2. Check online portals — banks and brokers increasingly deliver forms electronically only, and unclicked forms are a top cause of IRS mismatch letters.
3. Don't file the first week of February; corrected 1099s (especially from brokerages) commonly arrive through early March.
4. Verify the big numbers: W-2 Box 1 against your final paystub, 1099-B basis against your records.
5. Keep everything — digitally is fine — for at least 3 years, and 5498s / Roth records forever.

The arrival calendar

That calendar explains most filing-season frustration. Simple W-2 households can file accurately in early February. Anyone with a brokerage account should wait until at least late February, because consolidated 1099s get corrected — dividend reclassifications are routine — and filing before the corrections means amending later. And K-1 recipients (partnerships, some real estate deals) frequently can't file until March or must extend to October; the documents simply don't exist earlier. Your personal filing date should be set by your slowest form, not by the calendar's opening bell.

A last decoding tip: no form arriving doesn't mean no income. Banks skip 1099-INTs under $10 of interest, clients under $600 skip 1099-NECs, and foreign platforms may send nothing — yet all of it is taxable and reportable. The forms are the IRS's floor of knowledge, not the definition of your income. Report what happened; use the forms to check your work rather than define it.

The bottom line

Tax forms aren't a test — they're carbon copies of what the IRS already knows. Collect every form, report every form, fix the two famous errors (missing 1099-B basis and phantom 1099-K income), and file once the corrections settle. The people who get IRS letters aren't the ones who did complicated things; they're the ones who left a form in an unopened envelope.