IRS Forms & Notices Guide

The main federal tax return — almost everyone files this. It’s the form that pulls together all your income, deductions, and credits to figure out what you owe (or what you’re getting back).

The 1040 itself is relatively short. Most of the detail lives in numbered schedules that attach to it — Schedule 1 for additional income, Schedule A for itemized deductions, Schedule C for self-employment income, and so on. If you’re a standard W-2 employee with no side income, you may only need the 1040 itself. If your financial life is more complex, expect to attach a few schedules.

Brand-new form created by the One Big Beautiful Bill Act for 2025 returns (filed in 2026). Only file it if you’re claiming one of the four OBBBA deductions: the tips deduction, overtime deduction, car loan interest deduction, or the senior bonus deduction. If none of those apply, skip it.

Schedule 1-A lives alongside the regular numbered schedules but exists specifically for these four new deductions. Each deduction has its own income cap and eligibility rules — not every tip worker or senior automatically qualifies.

The form you give your employer to tell them how much federal income tax to withhold from your paycheck. Filling it out wrong is one of the most common reasons people owe a surprise bill at tax time — or get a giant refund (which just means you overpaid all year and loaned the government money interest-free).

You fill out the W-4 once when you start a job, and that’s usually the last time anyone thinks about it. But life changes — and so should your W-4.

The 1099 is the family of forms that reports income you received outside of a regular paycheck. There are over a dozen variants — here are the four most common ones most people will encounter.

You don’t fill these out yourself. Whoever paid you (a client, a platform, a brokerage) sends you one, and sends a copy to the IRS. Your job is to report the income on your return and make sure what you report matches what the IRS already has.

If you made money as a sole proprietor — freelancing, consulting, driving for Uber, selling on Etsy, running a one-person business — Schedule C is where you report it. You list your gross income at the top, subtract your legitimate business expenses, and the net number flows to your 1040.

Schedule C is where most small business deductions happen: home office, mileage, software subscriptions, professional services, supplies. Keep receipts for everything — if you get audited, “I just remember it was about $3,000” isn’t going to cut it.

If you netted $400 or more in self-employment income, you owe Social Security and Medicare tax on it — and you file Schedule SE to calculate it. W-2 employees split these taxes with their employer (7.65% each). Self-employed people pay both halves themselves, totaling 15.3%.

Schedule SE is short and mostly mechanical: plug in your Schedule C net profit, apply the 92.35% factor, multiply by 15.3% (up to the Social Security wage base), and you’ve got your SE tax.

Schedule A is where you itemize deductions instead of taking the standard deduction. The main categories are state and local taxes (SALT), mortgage interest, charitable contributions, and medical expenses above 7.5% of AGI.

Most people don’t itemize anymore. The 2017 tax law roughly doubled the standard deduction, and OBBBA pushed it higher still — which means itemizing only beats the standard deduction for homeowners in expensive areas, high earners with big charitable giving, and a handful of other cases.

Your employer’s record of what they paid you and what they withheld. You get one from every employer you worked for during the year, usually by late January. The numbers on the W-2 go directly onto your 1040 — Box 1 is wages, Box 2 is federal tax already withheld, Box 12 is where things like 401(k) contributions show up with letter codes.

You don’t fill out a W-2. Your employer does. Your job is to make sure the numbers match what your pay stubs showed all year, and to include it with your return.

Brand-new form created under OBBBA. Parents and other authorized individuals use it to open a Trump Account — a new type of tax-advantaged savings account for children under 18 — and to claim the one-time $1,000 federal pilot contribution for kids born 2025–2028.

You can file Form 4547 with your 2025 return (due April 15, 2026) or by itself at any time. Contributions to Trump Accounts can’t begin until July 4, 2026, but you need the election filed before then to have an account ready.

If you can’t file your tax return by April 15, submit Form 4868 and you automatically get an extra six months — pushing your filing deadline to October 15. No explanation required, no approval needed. The IRS grants the extension automatically.

The catch everyone misses: this is an extension to file, not an extension to pay. If you owe taxes, you still need to estimate what you owe and pay it by April 15. Otherwise, interest and late-payment penalties start accruing on the unpaid balance.

If your bank, brokerage, or credit union paid you more than $10 in interest during the year, they send you a 1099-INT. The number in Box 1 gets reported as taxable income on your 1040 (usually on Schedule B if you have multiple accounts or more than $1,500 in interest total).

This includes interest from regular savings accounts, CDs, money market accounts, corporate bonds, and Treasury bonds (though Treasury interest is federal-taxable only — your state can’t touch it).

If you own dividend-paying stocks, mutual funds, or ETFs, you’ll get a 1099-DIV reporting what they paid you. The critical split is between Box 1a (ordinary dividends, taxed at your regular income rate) and Box 1b (qualified dividends, taxed at the lower long-term capital gains rate).

Most dividends from U.S. stocks you’ve held long enough are qualified. Dividends from REITs and some foreign sources usually aren’t. Your brokerage sorts this out for you on the form.

If you have income that doesn’t have tax withheld from it — self-employment income, big investment gains, rental income, large IRA withdrawals — you generally need to pay estimated taxes four times a year instead of waiting until April. Form 1040-ES is both the worksheet that helps you figure out how much to pay and the voucher you send with your payment.

The quarterly deadlines are April 15, June 15, September 15, and January 15 of the following year. Miss them or underpay and you owe an underpayment penalty — even if you pay everything by April 15 the next year.

New form that crypto brokers and platforms started issuing for the 2025 tax year. If you bought, sold, swapped, or otherwise transacted in digital assets through a broker, you’ll get a 1099-DA showing the gross proceeds.

Heads up: the 1099-DA may not include your cost basis for every transaction. If your broker didn’t track what you originally paid, you need to use your own records to calculate gain or loss. Keep every trade confirmation — this is not the year to wing it on crypto reporting.

If you moved since filing your last return, use Form 8822 to tell the IRS your new address. It’s one page, takes two minutes, and prevents a surprising amount of tax-related trouble.

Why does this matter? Because the IRS sends all notices and refund checks to the last address on file. If a CP14 balance-due notice goes to your old place and sits unopened for 60 days, you can end up in collections on a debt you never knew existed. Most people who get to CP504 got there because earlier notices were sent somewhere they no longer lived.