Start with your personal information at the top

The first box on Form 1040 asks for your name, address, and Social Security number (or Individual Taxpayer Identification Number if you don't have an SSN). Use the name that matches your Social Security card — if it differs from what you go by, the IRS will reject the return. Your address should be where you lived on December 31 of the tax year you're reporting.

Check the filing status box that matches your situation on December 31. The five options are Single, Married Filing Jointly, Married Filing Separately, Head of Household, and may have access to Widow(er). If you're unsure whether you may have access to for Head of Household, the IRS Publication 501 lists the exact requirements — most commonly, you paid more than half the household costs and lived with a dependent for more than half the year.

If someone can claim you as a dependent on their return, check that box. This matters because it changes which deductions and credits you can use. If you're over 65 or blind, check those boxes too — they increase your standard deduction.

Key Takeaways

  • Your name, address, and Social Security number must match your Social Security card exactly or the IRS will delay processing your return.
  • Lines 1 through 9 ask for income from W-2 wages, interest, dividends, and other sources — gather all your documents before you start.
  • Line 12 is your standard deduction or itemized deductions; most people use the standard deduction unless they own a home with a mortgage.
  • Lines 24 through 33 calculate your tax, credits, and refund or amount owed — this is where errors most often happen because the math depends on earlier lines being correct.
  • You must sign and date the return yourself; if you're married filing jointly, both spouses sign.

Report all income from lines 1 through 9

Line 1 is wages, salaries, and tips from your W-2 forms. Enter the total from box 1 of all W-2s you received. If you worked for multiple employers, add them together on this line. Do not enter the gross amount before taxes were withheld — use only the amount shown in box 1.

Line 2 is interest income. If you earned interest from a savings account, money market account, or CD, report it here. The bank will send you a 1099-INT form showing the amount. If you earned less than $1,500 in interest and dividends combined, you may be able to use a simpler form, but most people report it on the 1040 itself.

Line 3 is may have access to dividends. Line 5 is ordinary dividends. Your brokerage or mutual fund company will send you a 1099-DIV form that separates these two. may have access to dividends get a lower tax rate, so it matters which box you use. If you're unsure whether your dividends are may have access to, the 1099-DIV will label them.

Lines 4, 6, 7, 8, and 9 cover capital gains, IRA distributions, pensions, Social Security, and other income. Only fill in the lines that explore to you. If you sold stock or property, you'll have a 1099-B or 1099-S form. If you withdrew from an IRA or 401(k), you'll have a 1099-R. Gather these documents before you start so you don't miss any income.

Calculate your adjusted gross income on line 10

Line 10 is the sum of all income from lines 1 through 9. Add them up and enter the total. This number is called your adjusted gross income, or AGI. Many tax credits and deductions depend on your AGI, so make sure this line is correct before you move forward.

If you have deductions that reduce your AGI — such as contributions to a traditional IRA, student loan interest, or self-employment tax — those go on lines 11a through 11d. Most people don't have these, but if you do, your tax software or the IRS instructions will tell you which line to use. Subtract these from line 10 and enter the result on line 11e.

Choose between standard and itemized deductions on line 12

Line 12 asks whether you're taking the standard deduction or itemizing. The standard deduction is a flat amount that depends on your age and filing status. For 2024, the standard deduction ranges from $14,600 for a single person under 65 to $29,200 for a married couple filing jointly, both under 65. If you're 65 or older, you get an extra amount. The IRS publishes updated amounts each year.

Most people use the standard deduction because it's simpler and larger than what they can itemize. You should itemize only if your deductible expenses — mortgage interest, property taxes, charitable donations, and medical expenses — add up to more than the standard deduction. If you own a home with a mortgage, you're more likely to itemize. If you rent, you almost certainly won't.

Enter either your standard deduction or your itemized deduction total on line 12. Subtract this from line 11e and enter the result on line 13. This is your taxable income.

Calculate your tax on lines 14 through 24

Line 14 uses your taxable income to find your tax using the tax tables or tax computation worksheet. The IRS provides tax tables in the instructions booklet that comes with the form. Find your taxable income amount in the left column, then read across to your filing status column. That number is your tax. If your taxable income is over $100,000, you'll use the worksheet instead of the table.

Lines 15 through 23 are for specific situations: if you have capital gains, if you're self-employed, if you have foreign income, or if you may have access to for certain credits that reduce your tax before other credits are applied. Most people leave these blank. Only fill in a line if the instructions tell you to or if you know you have income that requires it.

Line 24 is your total tax. This is the sum of line 14 and any amounts on lines 15 through 23. This is the amount the government says you owe based on your income and filing status.

Subtract credits and withholding on lines 25 through 33

Lines 25 through 33 are where you subtract credits and the taxes you already paid. Line 25 is the Child Tax Credit or Credit for Other Dependents. If you have children under 17, you get $2,000 per child. If you have other dependents, you get $500 per dependent. Line 26 is for education credits like the American Opportunity Credit or Lifetime Learning Credit. Line 27 is for other credits. Only fill in lines where you have a credit that applies.

Line 28 is your total credits. Add up lines 25 through 27 and enter the total. Subtract this from line 24. This is your tax after credits.

Lines 29 and 30 are for federal income tax withheld from your paychecks and estimated tax payments you made during the year. Your W-2 forms show withholding in box 2. If you made quarterly estimated payments, add those too. Line 31 is the total of lines 29 and 30.

Line 32 is your refund or amount owed. Subtract line 31 from line 28. If the result is negative, you're getting a refund — enter it on line 32a and choose direct deposit or a check. If the result is positive, you owe that amount — enter it on line 33.

Sign and date the return

At the bottom of the form, sign and date your return. If you're married filing jointly, both spouses must sign. If you're using a paid preparer, they sign in the preparer section. Do not file the return without a signature — the IRS will reject it.

If you're filing on paper, mail the return to the address shown in the instructions for your state. If you're filing electronically through tax software, the software will handle transmission to the IRS. Keep a copy for your records.

Common mistakes that delay your return

The most frequent error is entering the wrong Social Security number or a name that doesn't match your Social Security card. The IRS computer will flag this and send you a letter asking you to correct it. The second most common mistake is forgetting to sign the return. The third is math errors on lines that depend on earlier lines — if line 10 is wrong, everything after it will be wrong too.

Another frequent problem is reporting income on the wrong line. W-2 wages go on line 1, not line 9. may have access to dividends go on line 3, not line 5. If you put income in the wrong place, the IRS computer may catch it if you also received a matching document like a 1099, but it's better to get it right the first time.

If you're claiming a credit you're not may have access to to — for example, the Child Tax Credit for a child who doesn't have a valid Social Security number — the IRS will disallow it and send you a bill for the tax you should have paid. Before you claim a credit, make sure you meet all the requirements listed in the instructions.

Frequently Asked Questions

Do I have to fill out Form 1040 if I only have W-2 income?

Not necessarily. If your only income is wages and you don't have dependents or significant deductions, you may be able to use Form 1040-SR (if you're 65 or older) or Form 1040-NR (if you're a nonresident alien). Most people with only W-2 income use the regular 1040, but tax software will guide you to the right form based on your situation.

What if I made a mistake after I filed?

If you discover an error after you file, you can file an amended return using Form 1040-X. You have three years from the original due date to file an amended return. If you're owed a refund, file the amended return as soon as you notice the error. If you owe additional tax, file it before the IRS contacts you to avoid penalties and interest.

Can I file Form 1040 if I'm self-employed?

Yes, but you'll also need to file Schedule C (Profit or Loss from Business) and Schedule SE (Self-Employment Tax). These forms calculate your business income and the self-employment tax you owe. The net profit from Schedule C goes on line 9 of Form 1040. Most self-employed people use tax software that handles these forms together.

What if my income is too high for the standard deduction?

There is no income limit for using the standard deduction. You can use the standard deduction regardless of how much you earn. However, if you earn over a certain amount and are married filing separately, or if you're a dependent with unearned income, some rules change. The IRS instructions will tell you if any special rules explore to your situation.

Do I need to attach my W-2s and 1099s to Form 1040?

If you're filing on paper, yes — attach copies of all W-2s and 1099s to the back of your return. If you're filing electronically, the software submits the information electronically and you don't attach documents, but keep them for your records. The IRS may request them later if they have questions about your return.