ITIN resource centre
How to file a U.S. tax return
Six steps, in order: gather your documents, establish which return applies to you, choose a filing status, settle your deductions, file, and pay or claim your refund. Here is what each one involves, and where people most often go wrong.
Written and reviewed by Mr. Bryan Woods, MBA, IRS Certifying Acceptance Agent
Gather your documents
Almost every problem with a return traces back to a missing piece of paper. Collect everything before you start; a return prepared from a complete file takes a fraction of the time and stands up to scrutiny.
Income
- Form W-2 — wages from an employer, and the tax already withheld
- Form 1099-NEC / 1099-MISC — contract, freelance and miscellaneous income
- Form 1099-INT / 1099-DIV — bank interest and dividends
- Form 1099-B — sales of shares and securities
- Form 1099-R — pensions, annuities and retirement distributions
- Form 1042-S — U.S. income paid to a foreign person, and treaty withholding
- Form K-1 — your share from a partnership, S corporation or trust
- Rental income and expense records
- Foreign income, converted to U.S. dollars
Deductions and credits
- Form 1098 — mortgage interest paid
- Form 1098-T / 1098-E — tuition, and student loan interest
- State and local property and income tax paid
- Charitable donation receipts
- Medical and dental expenses
- Retirement and health savings contributions
- Childcare costs, with the provider’s tax number
- Business expenses, if self-employed
- Foreign tax paid, for the foreign tax credit
Identification
- Your SSN or ITIN — and one for your spouse and each dependent
- Full legal names and dates of birth, exactly as the IRS holds them
- Last year’s return, if you have one
- Bank account and routing numbers, for a refund by direct deposit
- Passport and visa details, if you are not a citizen
- A record of days present in the United States, for the residency test
No SSN or ITIN yet? The return cannot be processed without one. Form W-7 is normally filed together with the return — we handle both as a single package. As a Certifying Acceptance Agent we send the IRS a certified copy of your passport, never the passport itself: we touch and hold the original only to confirm it is valid, photocopy it, and courier it back to you within one to two days.
Apply for an ITINWork out which return you file
Form 1040
Citizens, Green Card holders, and residents for tax purposes
You report worldwide income and claim the full range of deductions and credits, including the standard deduction. You are a resident for tax purposes if you hold a Green Card or if you met the substantial presence test — broadly 31 days in the current year and 183 on a weighted three-year count.
Form 1040-NR
Non-resident aliens
You report only U.S.-connected income. The rules are narrower: most non-residents cannot take the standard deduction, the available filing statuses are limited, and dependents can generally only be claimed in specific circumstances. Treaty positions are claimed on this return.
The year you arrive or leave
A year in which your status changes part-way through is a dual-status year, and it is genuinely complicated — part of the year is taxed on one basis and part on the other. There are also elections that can let a spouse be treated as a resident for the whole year, which sometimes produces a much better result. This is worth an hour of professional attention rather than a guess.
Choose your filing status
Filing status sets your tax brackets and your standard deduction, so it moves the final number more than almost any other single choice on the return. Your status is determined by your circumstances on the last day of the tax year.
| Status | Who it is for |
|---|---|
| Single | Unmarried, divorced or legally separated at year end, and not qualifying as head of household. |
| Married filing jointly | One return for both spouses, with the widest brackets and the largest standard deduction. Usually the cheapest outcome — and the reason so many ITIN applications are filed for a non-citizen spouse. Both spouses are jointly responsible for the tax. |
| Married filing separately | Separate returns. Generally more tax overall and several credits are lost, but sometimes right — to keep liabilities apart, or where one spouse’s deductions or income-based obligations make it worthwhile. |
| Head of household | Unmarried (or treated as such), paying more than half the cost of a home for a qualifying person. Better brackets and a larger deduction than single. Frequently missed by people who qualify. |
| Qualifying surviving spouse | Available for a limited number of years after a spouse’s death where there is a dependent child, giving joint-return brackets. |
Standard deduction, or itemise?
Take the standard deduction
A flat amount subtracted from your income, set by your filing status and adjusted for inflation each year, with additions for taxpayers who are 65 or older or blind. No receipts, no schedules, no arguments. Most filers are better off here, and since the amounts were raised substantially the great majority take it.
Note: most non-residents filing Form 1040-NR cannot claim it, though a treaty may provide otherwise.
Itemise your deductions
Add up your actual qualifying expenses instead — mortgage interest, state and local taxes (capped), charitable gifts, and medical costs above a percentage of your income. Worth doing when the total beats the standard amount, which most often happens for homeowners with a large mortgage, people in high-tax states, significant donors, or a year with heavy medical bills.
You calculate both and take the larger. It is not a matter of preference.
Deduction amounts, brackets and the various caps are indexed and change from year to year, so we have deliberately not printed figures here that would quietly go out of date. Current amounts are on irs.gov, and we apply the correct year’s numbers when we prepare a return.
File the return
Electronically
Fastest to process, fastest to refund, and the software catches arithmetic errors before the IRS does. You get an acknowledgement that the return was accepted — a receipt that paper filing does not give you.
On paper
Still necessary in some situations — notably a first-time ITIN application, where Form W-7 and the return travel together to the IRS ITIN Operation. Use a tracked service and keep proof of the postmark date.
Through a professional
Sensible where there is an ITIN application, a treaty claim, foreign income, rental property, a dual-status year or unfiled years to resolve. These are the returns where the cost of a mistake exceeds the cost of help.
Sign it
An unsigned return is not a filed return. On a joint return both spouses sign. This is the most avoidable reason a paper return comes back, and it costs weeks.
Pay what you owe — or get your refund
If you owe tax
- Direct from a bank account. The IRS offers free direct payment from a U.S. account, and payment can be scheduled for the due date.
- Card. Accepted through approved processors, which charge their own fee.
- Wire from abroad. Available where you have no U.S. bank account; allow extra days.
- Instalments. If you cannot pay in full, a payment plan is usually available. Interest continues, but the far heavier late-filing penalty stops the moment you file.
File on time even if you cannot pay on time. They are two separate penalties, and the filing one is much larger.
If you are due a refund
Direct deposit to a U.S. bank account is quickest — typically a few weeks on an electronically filed return, against several times that for a paper one. A refund on a return filed alongside a first ITIN application waits for the number to be issued first.
You can track progress with the IRS’s own Where’s My Refund service. Checking daily will not speed it up; the file updates once a day at most.
Refunds expire. A claim must generally be made within about three years of the due date. After that the money stays with the Treasury, however clearly it was yours.
The dates that matter
| Date | What it is |
|---|---|
| 15 April | The deadline for most individual returns, and for paying the tax. Shifts to the next business day when it falls on a weekend or holiday. |
| 15 June | The automatic extended deadline for citizens and residents living abroad, and for non-residents who had no U.S. wages subject to withholding. Tax still accrues interest from April. |
| 15 October | The deadline once you have requested an extension. An extension of time to file, not to pay. |
| Quarterly | Estimated tax instalments, if your income is not covered by withholding — self-employment, rents, investments. Missing these carries its own penalty. |
| ~3 years | The window to claim a refund, or to amend a return you have already filed. |
Applying for an ITIN? Start early
Where a first-time ITIN application and a return go in together, the IRS handles the ITIN first — commonly seven weeks, and nine to eleven in the January-to-April crush. Beginning in the autumn or early winter, rather than in April, is the single easiest way to avoid a slow season. There is no penalty for being early.
Start an ITIN application nowMistakes we see most often
A name or number that does not match IRS records
One transposed digit, or a married name the IRS has not been told about, and the return is rejected. Check every identification number against the card or notice, not from memory.
Filing with an expired ITIN
Three consecutive years unused and it stops working. The return is processed without the exemptions and credits that relied on it, and the correction takes months.
Filing 1040 when 1040-NR was right, or the reverse
The wrong return means the wrong deductions and the wrong tax. Establish residency status first — especially in a year of arrival or departure.
Leaving out foreign income or accounts
Citizens and residents report worldwide income, and foreign accounts carry separate reporting duties with severe penalties. Information now flows to the IRS from foreign banks directly.
Assuming a treaty removes the need to file
A treaty benefit is usually claimed on a return. Not filing does not claim it — it forfeits it.
Not filing because you cannot pay
The most expensive mistake on this list. Filing without paying costs a fraction of doing neither, and a payment plan is usually available.
Read next
Who must file a U.S. tax return
Worldwide income for citizens and Green Card holders, and the five categories of non-citizens with a duty to file.
ITIN basicsWho needs an ITIN
The five categories of applicant, the documents the IRS accepts, and the exceptions to attaching a return.
Ready to apply, or still not sure?
Mr. Bryan Woods is an IRS Certifying Acceptance Agent, so your passport is never sent to the IRS. We touch and hold it only long enough to confirm it is valid and photocopy it — one to two days — then courier it straight back to you. Start the online application, or call and talk it through first — both are free.
Please note. This page is general information about United States federal tax rules, not advice about your own circumstances, and rules change. ITIN INTERNATIONAL TAX SERVICES is a private firm authorised by the Internal Revenue Service as a Certifying Acceptance Agent; we are not a government agency and we are not affiliated with the IRS beyond that authorisation. Form W-7 and its instructions are available free of charge from irs.gov. For advice on your situation, please get in touch.