How to File a US Tax Return Step by Step (2026)

To file a US federal tax return, you submit Form 1040 (or Form 1040-NR if you are a non-resident alien) to the Internal Revenue Service, reporting your income, deductions, and credits for the prior tax year. Most individual filers have an April deadline, can file electronically for free through IRS-approved software, and receive any refund within a few weeks of acceptance. The process has eight clearly defined stages — and this guide works through each one.

Who This Guide Is For

This guide is written for individuals who need to file a US federal income tax return: residents, citizens, and internationally mobile workers with US tax obligations. It covers calendar-year filers submitting a return in 2026 for tax year 2025. It is practical information, not tax advice. Where your situation is complex — foreign income, multiple states, self-employment, or non-resident alien status — verify your position with a licensed Certified Public Accountant (CPA), Enrolled Agent (EA), or tax attorney.

Do You Actually Need to File?

Before spending time on forms, confirm whether you are legally required to file, or whether filing is simply in your interest even if not strictly required.

The IRS sets annual gross-income thresholds that trigger a filing requirement. These vary by filing status (single, married filing jointly, married filing separately, head of household, qualifying surviving spouse) and by age. The authoritative source is IRS Publication 501, Dependents, Standard Deduction, and Filing Information, updated each year at irs.gov.

Even if your income falls below the threshold, you should generally file if:

• Tax was withheld from your wages and you want a refund.
• You qualify for refundable credits such as the Earned Income Tax Credit (EITC) or the Additional Child Tax Credit.
• You are self-employed with net earnings of $400 or more (the self-employment tax threshold).
• You received advance payments of a premium tax credit through the health insurance marketplace.

Non-resident aliens with US-source income have different thresholds and file Form 1040-NR. If you are on a work visa — H-1B, L-1, O-1, or similar — your filing status depends heavily on how many days you have been physically present in the US; the Substantial Presence Test in IRS Publication 519 determines this. For context on the range of visa categories that bring workers to the US, see the overview of H Visa Types Explained: H-1B, H-2A and H-2B in 2026.

Step 1: Gather Your Documents

Filing is largely a document-assembly exercise. Start collecting the following before you open any software.

Income Documents

Employers and payers must send these forms by 31 January (W-2s, 1099-NECs) or mid-February (certain 1099s). If a document has not arrived by mid-February, contact the issuer. If you still cannot get it, IRS Form 4852 (Substitute for Form W-2) can be used as a last resort.

Deduction and Credit Records

• Mortgage interest statements (Form 1098).
• Student loan interest paid (Form 1098-E).
• Tuition paid (Form 1098-T) for the American Opportunity or Lifetime Learning Credits.
• Records of charitable contributions — cash and non-cash.
• Medical expense receipts if you expect to itemise.
• Business expense records if you are self-employed (you will complete Schedule C).
• Childcare provider details (name, address, Tax Identification Number) for the Child and Dependent Care Credit.
• Prior-year state tax refunds (these may be taxable if you itemised deductions last year).
• Your prior-year AGI (Adjusted Gross Income) — required by e-filing systems to authenticate identity.

Identity Information

• Social Security Numbers (SSNs) or Individual Taxpayer Identification Numbers (ITINs) for yourself, your spouse, and all dependants.
• Your bank account number and routing number for direct deposit of any refund.

Step 2: Choose Your Filing Status

Your filing status determines your standard deduction, tax brackets, and eligibility for many credits. The five statuses are: Single, Married Filing Jointly, Married Filing Separately, Head of Household, and Qualifying Surviving Spouse. The IRS Interactive Tax Assistant tool at irs.gov can help you determine your correct status if you are unsure.

Married filing separately is almost always the least favourable option financially, but it is sometimes chosen for legal separation or liability reasons. It also disqualifies you from the EITC, student loan interest deduction, and the Child and Dependent Care Credit, among others.

Step 3: Choose the Right Form

Form 1040 vs 1040-SR vs 1040-NR

Form 1040 is the standard individual income tax return for US citizens and resident aliens. It replaced the old 1040A and 1040EZ forms, which no longer exist.

Form 1040-SR is a version of the 1040 with larger print, designed for filers aged 65 or older. It is functionally identical; you may use either.

Form 1040-NR is for non-resident aliens. It has different lines, a different standard deduction structure (non-residents generally cannot claim the standard deduction), and different treaty benefit claims. If you are uncertain whether you are a resident or non-resident for tax purposes, work through the Substantial Presence Test in IRS Publication 519 or consult a cross-border tax professional.

Common Schedules Attached to Form 1040

Step 4: Decide Between Standard Deduction and Itemising

For most filers, the standard deduction is simpler and higher than their itemised total. For tax year 2025 returns filed in 2026, the IRS announces the standard deduction amounts in autumn of the prior year. Verify the exact figures for your filing status at irs.gov/taxtopics/tc551 or in the Form 1040 instructions.

When Itemising Makes Sense (Worked Illustrative Example)

Illustrative only — not a prediction of your outcome.

Sofia is a single homeowner. Her 2025 deductible figures are:

• Mortgage interest (Form 1098): $9,800
• State and local taxes (SALT, capped at $10,000): $10,000
• Charitable contributions: $2,400
• Total itemised: $22,200

If the 2025 standard deduction for a single filer is approximately $15,000 (illustrative — verify at irs.gov), Sofia would save more tax by itemising. She completes Schedule A and attaches it to her 1040.

Her colleague Marco has no mortgage, modest state taxes of $4,200, and small charitable gifts of $600. His itemised total of $4,800 is far below the standard deduction. He takes the standard deduction — no Schedule A needed.

Step 5: Calculate Your Tax

Adjusted Gross Income (AGI) First

AGI is the foundation of your return. It is gross income minus specific "above-the-line" adjustments, which include:

• Student loan interest (up to statutory limits).
• Contributions to a traditional IRA (subject to income phase-outs).
• Self-employed health insurance premiums.
• Alimony paid under pre-2019 divorce agreements.
• Contributions to a Health Savings Account (HSA) — Form 8889.

Your AGI determines eligibility for many credits and deductions. Modified AGI (MAGI) is a further variant used for specific purposes such as Roth IRA eligibility; the definition of MAGI varies by context.

Taxable Income and Tax Brackets

Subtract your standard or itemised deduction (and any Qualified Business Income deduction under Section 199A if applicable) from AGI to reach taxable income. Apply the federal income tax brackets — a progressive marginal rate system. For 2025 rates, refer to the IRS Revenue Procedure published in the autumn of 2024 or see IRS Publication 17.

Tax Credits Reduce Your Bill Directly

Deductions reduce the income on which tax is calculated. Credits reduce the tax itself, dollar for dollar. Key credits include:

• Child Tax Credit — per-child credit, with a partially refundable Additional Child Tax Credit component.
• Earned Income Tax Credit (EITC) — refundable; targeted at lower-to-moderate income workers; eligibility and amounts vary significantly by number of children.
• Child and Dependent Care Credit — for childcare costs that allow you to work.
• American Opportunity Tax Credit (AOTC) — up to $2,500 per eligible student; 40% refundable.
• Premium Tax Credit — for health insurance purchased through the marketplace.

Verify current amounts and phase-out thresholds in IRS Publication 17 or the relevant form instructions.

Step 6: File Electronically or by Paper

Electronic Filing (E-file)

E-filing is faster, more accurate, and provides an IRS acceptance confirmation, typically within 24–48 hours. The IRS processes e-filed refunds via direct deposit in around 21 days under normal circumstances (though this is not guaranteed).

IRS Free File: If your AGI falls below the programme threshold (roughly $79,000 for 2025 — confirm at irs.gov/freefile), you can use brand-name software at no cost through the official IRS Free File programme. Access only via irs.gov; third-party sites may charge fees.

IRS Free File Fillable Forms: Available to all filers regardless of income, these are electronic versions of paper forms with basic calculation assistance. They require more tax knowledge than guided software.

Commercial software: Products such as TurboTax, H&R Block, TaxAct, and FreeTaxUSA walk you through questions and populate the return. Costs vary. Many offer free tiers for simple returns.

Tax professional e-filing: A CPA, EA, or paid preparer will typically e-file on your behalf using professional software.

Paper Filing

Mail your completed return to the IRS service centre for your state. Addresses vary depending on whether you are enclosing payment. Find the correct address in the Form 1040 instructions or at irs.gov. Use certified mail and keep the receipt — postmark date determines timely filing.

Step 7: Pay Any Tax Owed

If your return shows a balance due, pay by the filing deadline to avoid interest and penalties.

IRS Direct Pay: Free bank transfer directly from a checking or savings account via irs.gov/payments — no registration required for occasional use.

EFTPS (Electronic Federal Tax Payment System): Best for those making regular payments (estimated tax, business payments). Registration required in advance at eftps.gov.

Debit or credit card: Accepted through IRS-authorised payment processors. A convenience fee applies.

Check or money order: Made payable to "United States Treasury", with your SSN, tax year, and form number on the memo line. Do not staple to your return.

Estimated Tax Payments

If you are self-employed, have significant investment income, or expect to owe $1,000 or more in federal tax after withholding, you may need to make quarterly estimated payments using Form 1040-ES. Underpayment can result in an underpayment penalty calculated on Form 2210. Quarterly due dates typically fall in April, June, September, and January — verify exact dates at irs.gov.

Step 8: Keep Records After Filing

Once filed, retain copies of:

• Your complete tax return and all supporting schedules.
• All W-2s and 1099s.
• Receipts supporting deductions claimed.
• Proof of payment if you owed tax.

The IRS generally has three years from the filing date to audit a return, six years if it suspects a substantial understatement of income, and no time limit for fraud. Keep property records (including cost basis for investments) until you sell the asset and then for three years beyond the return on which you report the sale.

Common Filing Mistakes — and How to Fix Them

1. Wrong Social Security Number. A transposed digit on a dependent's SSN will reject a credit claim. Double-check every SSN against the Social Security card. Fix after filing with Form 1040-X.

2. Forgetting 1099-NEC income. The IRS receives copies of all 1099s. Omitting freelance income triggers automated CP2000 notices. Cross-reference every 1099 against your bank deposits before filing.

3. Claiming the wrong filing status. Head of Household (HOH) rules are specific: you must be unmarried (or considered unmarried), have paid more than half the home's cost, and have a qualifying person living with you for more than half the year. Incorrectly claiming HOH is a frequent audit trigger.

4. Missing out on the EITC. The EITC has complex eligibility rules and is commonly under-claimed. The IRS EITC Assistant tool at irs.gov checks eligibility. It is also commonly over-claimed by those whose investment income exceeds the annual limit — read the rules carefully.

5. Not reporting foreign financial accounts. US persons with foreign bank or financial accounts totalling more than $10,000 at any point during the year must file FinCEN Form 114 (FBAR) separately from their tax return, via the BSA E-Filing System. Separately, Form 8938 (FATCA) may be required on the tax return itself. Penalties for non-compliance are severe. Consult a cross-border tax professional.

6. Missing the deadline without filing for an extension. The failure-to-file penalty (5% per month, up to 25% of unpaid tax) dwarfs the failure-to-pay penalty. If you cannot complete your return by April, file Form 4868 by the deadline to extend the filing date. Pay your best estimate of tax owed at the same time.

7. Using the wrong bank details for direct deposit. A refund directed to a closed account or a third party's account creates weeks of delays. The IRS will generally reissue by cheque, but this takes time. Verify routing and account numbers carefully.

8. Not signing the return. An unsigned paper return is not valid. Both spouses must sign a married filing jointly return. If using a paid preparer, they must sign and include their Preparer Tax Identification Number (PTIN).

Special Situations Worth Flagging

Working Abroad or Living in Multiple Countries

US citizens and permanent residents are taxed on worldwide income. If you earned income in another country, you may claim the Foreign Earned Income Exclusion (FEIE) via Form 2555 (subject to a statutory annual limit that adjusts for inflation — verify at irs.gov) or the Foreign Tax Credit via Form 1116. These are powerful but rule-heavy provisions. A professional who handles international returns is worth the cost.

If you have recently moved abroad for a sponsored job, you may find the broader financial planning considerations around relocation useful — see Relocation Costs When Moving for a Sponsored Job 2026.

Self-Employment

Self-employed individuals report business profit and loss on Schedule C and calculate self-employment tax on Schedule SE. You pay both the employee and employer halves of Social Security and Medicare taxes — effectively 15.3% on net self-employment income up to the Social Security wage base, then 2.9% (Medicare) above that. You may deduct the employer-equivalent portion of SE tax as an above-the-line adjustment on Form 1040.

State and Local Returns

This guide covers federal returns only. Most states with an income tax require their own return, filed separately. Nine states currently have no income tax on wages (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, Wyoming — but verify as legislation changes). If you lived or worked in more than one state during the year, you may need to file in multiple states.

International Workers on US Work Visas

If you are working in the US on an H-1B, H-2A, or other sponsored work visa and have not yet reached the Substantial Presence threshold, your filing obligations differ materially from a resident. Many workers on sponsored visas who plan a longer-term move to the US — or who eventually pursue green card routes such as the EB-2 National Interest Waiver — benefit from tax planning advice early, before certain elections become irrevocable.

Where to Get Help

When selecting a paid preparer, verify their PTIN at irs.gov/tax-professionals/verify-the-status-of-an-enrolled-agent. Be cautious of any preparer who charges fees based on your refund size or promises a large refund before seeing your documents. These are red flags. Similarly, no legitimate tax service will ask you to pay preparation fees via gift card or wire transfer — for more on spotting financial and service scams in contexts where you are dealing with paperwork and professionals, the principles in Common Visa Sponsorship Scams and How to Spot Them apply by analogy.

A Note on State Returns and Software Costs

Major commercial tax software bundles federal and state filing together, but often charges separately for a state return. If cost is a concern, IRS Free File partner products sometimes include free state filing for certain states. Some state revenue departments also offer their own free filing portals. Always check your state revenue department's website directly.

Quick-Reference Filing Checklist

Before you submit:

• [ ] All W-2s and 1099s collected and checked against your own records.
• [ ] Filing status confirmed and correct.
• [ ] SSNs/ITINs for every person on the return verified against official documents.
• [ ] Standard deduction vs itemising decision made deliberately.
• [ ] Above-the-line adjustments claimed (IRA, student loan interest, HSA, etc.).
• [ ] All applicable credits reviewed (EITC, Child Tax Credit, AOTC, etc.).
• [ ] Foreign income, accounts, and assets addressed if applicable.
• [ ] Bank account details for direct deposit triple-checked.
• [ ] Return signed (and, if applicable, dated by paid preparer with PTIN).
• [ ] Copy of completed return saved to a secure location.
• [ ] Form 4868 filed if you cannot complete on time and a balance is due.

All figures and thresholds in this article are illustrative or sourced from IRS publications current at time of writing. Tax rules change annually. Verify all amounts, deadlines, and eligibility conditions at irs.gov or through a qualified tax professional before filing. This article is general practical information, not individualised tax advice.