Short answer
Your first question is not which form to use — it is whether you are a resident or a non-resident alien for tax purposes. Residents file Form 1040 and report worldwide income. Non-residents file Form 1040-NR and report only US-source income. The substantial presence test decides which one you are, and visa type can override it.
On this page
- Start with one question: resident or non-resident?
- The green card test
- The substantial presence test
- The exception that covers most students and scholars
- What each status means in practice
- The numbers for this filing season
- Your number: SSN or ITIN
- The forms that will arrive in your post
- How to file
- Settle your status
- Collect every form
- Choose the right route
- Do not forget the state
- File by the deadline, even if you cannot pay
- Two things people abroad forget
- Watch your withholding
- Nobody from the IRS is going to phone you
- When to pay for help
- Frequently asked questions
Key takeaways
- “Resident for tax” and “resident for immigration” are different tests with the same word. You can be one without the other.
- The substantial presence test counts days across three years, weighted. F and J visa holders are often exempt from counting days for their first years.
- You need an SSN, or an ITIN if you are not eligible for one — Form W-7, usually filed with your first return.
- For tax year 2025 the standard deduction is $15,750 single and $31,500 married filing jointly; for 2026 it rises to $16,100 and $32,200.
- Non-resident aliens generally cannot claim the standard deduction, which is why status matters so much.
What you will need
- Your SSN, or an ITIN (Form W-7) if you are not eligible for one
- A W-2 from every employer you had during the year
- Any 1099, 1042-S, 1098-T or 1095 forms you received
- A record of the days you were physically present in the US
- Your visa history, for the exempt-individual test
- Details of any foreign accounts and foreign income
In much of the world, tax simply happens to you. Your employer deducts the right amount, the year ends, and nobody sends you a form. The United States works the other way round: your employer withholds an estimate, and then it is your job to work out what you actually owed and settle the difference.
That is the whole shock, and it is a procedural one rather than a difficult one. This guide walks through the question that determines everything else, the forms that follow from it, the numbers for the current filing season, and the traps that cost newcomers real money.
Start with one question: resident or non-resident?
Before any form, you must know whether you are a resident alien or a non-resident alien for tax purposes. Everything downstream depends on it.
The critical thing to understand is that this has nothing to do with your immigration status. You can be a non-immigrant visa holder and be a resident for tax purposes, or a lawful visitor and not be. Same word, two entirely different tests.
The green card test
If you are a lawful permanent resident at any point in the calendar year, you are a resident for tax purposes. Simple.
The substantial presence test
Otherwise you count days. You are a resident for the year if you were physically present in the US for:
- at least 31 days during the current year, and
- at least 183 days over three years, counting all days this year, one third of last year's days, and one sixth of the days from the year before that.
So 120 days in each of three years is 120 + 40 + 20 = 180 days. Not a resident. One more month this year and you are.
The exception that covers most students and scholars
Certain people are exempt individuals — meaning their days do not count at all towards the test, not that they are exempt from tax. Students on F, J, M and Q visas are usually exempt individuals for their first five calendar years; teachers and trainees on J and Q visas are usually exempt for two of the previous six.
This is why a student who has lived in the US continuously for three years is very often still a non-resident for tax purposes and must file a completely different return from the one their classmates file.
Which tax return do you file?
The commonest expensive mistake
A non-resident who files Form 1040 with ordinary consumer tax software, claims the standard deduction they are not entitled to, and receives a refund they were never owed. It is easy to do — most mainstream software does not even ask — and it produces a return that has to be amended, sometimes years later. If you might be a non-resident, establish that before you open any software.
What each status means in practice
| Resident alien | Non-resident alien | |
|---|---|---|
| Main form | Form 1040 | Form 1040-NR |
| Income taxed | Worldwide income | US-source income only |
| Standard deduction | Yes | Generally no (limited treaty exceptions) |
| Filing jointly with a spouse | Yes | Generally no |
| Most tax credits | Generally available | Sharply limited |
| Social Security and Medicare tax | Withheld from wages | Often exempt for F and J students on authorised work |
| Foreign account reporting | Applies if thresholds met | Generally not |
The numbers for this filing season
The standard deduction is the amount a resident can subtract from income before tax is calculated. It rose under legislation enacted in 2025.
| Filing status | Tax year 2025 (filed in 2026) | Tax year 2026 (filed in 2027) |
|---|---|---|
| Single / married filing separately | $15,750 | $16,100 |
| Married filing jointly | $31,500 | $32,200 |
| Head of household | $23,625 | $24,150 |
Non-resident aliens generally cannot claim any of this, which is the single biggest financial consequence of the resident/non-resident distinction. A narrow treaty-based exception exists for some students from certain countries.
Your number: SSN or ITIN
To file, you need a taxpayer identification number. If you are eligible for a Social Security number, that is your number.
If you are not eligible — most commonly a spouse or dependant without work authorisation — you apply for an ITIN on Form W-7. Three points save people a lot of trouble:
- The W-7 is normally filed with the tax return, not before it.
- You must prove identity and foreign status with original documents or agency-certified copies.
- You do not have to post your passport to the IRS. A Certified Acceptance Agent, or an IRS Taxpayer Assistance Center by appointment, can verify documents in person and hand them back.
ITINs can expire if unused for several consecutive years. If you have an old one, check whether it is still valid before filing season starts.
The forms that will arrive in your post
| Form | Sent by | What it tells you |
|---|---|---|
| W-2 | Your employer | Wages paid and tax already withheld — you were an employee |
| 1099-NEC | A company that paid you | Contractor income with nothing withheld — you owe the tax |
| 1099-INT / 1099-DIV | Bank or broker | Interest or dividends earned |
| 1042-S | Employer or institution | Payments to a non-resident, often treaty-related |
| 1098-T | Your university | Tuition paid — relevant to education credits for residents |
| 1095-A/B/C | Insurer or employer | Health coverage during the year |
W-2 or 1099 is not your choice — or your employer's
Being paid on a 1099 means no tax is withheld, and you owe both halves of Social Security and Medicare — roughly 15.3% self-employment tax — on top of income tax. If you receive a 1099 for work that looked like a normal job with set hours and supervision, you may have been misclassified. That is worth raising, because the difference is thousands of dollars.
How to file
-
Settle your status
Work through the substantial presence test, including the exempt-individual rules, before anything else. Write down the answer and why.
-
Collect every form
Employers must send W-2s by the end of January. If you changed jobs, you need one from each. Missing a form is the most common cause of a corrected return later.
-
Choose the right route
Residents with straightforward affairs can often file federal returns free through the IRS Free File programme, and free in-person help exists for people on lower incomes and for older filers. Non-residents need software that specifically supports Form 1040-NR — many universities provide access to exactly that for their international students, so ask before you pay.
-
Do not forget the state
Most states levy their own income tax with their own rules, forms and deadlines. A few levy none at all. If you moved between states during the year, you may need to file in both as a part-year resident.
-
File by the deadline, even if you cannot pay
The federal deadline is normally 15 April. An extension is easy to obtain and gives you more time to file — it does not give you more time to pay. The penalty for failing to file is far larger than the penalty for failing to pay, so always file.
Two things people abroad forget
Worldwide income. If you are a resident for tax purposes, the US taxes what you earn anywhere — rent from a flat back home, interest in a foreign bank, freelance work for a client overseas. Double taxation is usually prevented by the foreign tax credit or by a treaty, but only if you report the income in the first place.
Foreign accounts. If you are a US person for tax purposes and your foreign financial accounts combined exceeded $10,000 at any moment during the year, you must file an FBAR with the Treasury. It is separate from your tax return, it is filed electronically, and it is quick. The penalties for ignoring it are severe and wildly out of proportion to how easy it is to do.
Watch your withholding
Your employer withholds based on the Form W-4 you completed on your first day, probably in a rush. If too little is withheld you get a bill in April; if too much, you have given the government an interest-free loan all year.
Check it once, a few months into any new job, using the IRS withholding estimator, and hand payroll a corrected W-4 if the numbers are off. Households with two earners and people who also have 1099 income are the ones most often surprised.
Nobody from the IRS is going to phone you
Filing season brings a wave of scams aimed squarely at people who are new to the system and unsure what is normal. The IRS initiates contact by post. It does not call demanding immediate payment, it does not text, it does not email asking for bank details, it does not threaten arrest or deportation, and it never asks to be paid in gift cards or cryptocurrency.
If you receive a letter that looks genuine, do not use the phone number printed on it — look up the IRS number independently and call that.
When to pay for help
A single W-2, no dependants and no foreign income is a return you can file yourself in an evening. Get help when any of these apply: you were a non-resident or changed status mid-year; you have 1099 or self-employment income; you own property or hold significant assets abroad; a tax treaty might apply; or you moved between states.
Look for an Enrolled Agent or a CPA with experience of international filers, and ask directly whether they handle Form 1040-NR and treaty positions. Free IRS-sponsored preparation programmes exist for lower-income filers and older taxpayers, and many universities run free clinics for international students. All of those are better than guessing.
One last thing: keep your returns. A filed tax return is one of the strongest proofs of income in the country, and it will be asked for when you rent, borrow, or apply for a change of status. It works alongside the credit file you are building — see building a US credit score from zero.
Frequently asked questions
Am I a resident or non-resident alien for tax purposes?
You are a resident for tax purposes if you hold a green card, or if you meet the substantial presence test: at least 31 days in the current year and 183 days counting all of this year's days, one third of last year's and one sixth of the year before. Students on F visas and scholars on J visas are usually exempt individuals for an initial period and do not count those days.
Do I have to file if I earned very little?
Often you are not required to — but you should anyway if tax was withheld, because filing is how you get it back. Non-resident aliens have a separate obligation: many must file an informational form even with no US income at all. Not filing when you should is far more expensive than filing when you did not have to.
What is an ITIN and how do I get one?
An Individual Taxpayer Identification Number is a tax processing number for people who must file but cannot get an SSN — commonly a spouse or dependant. You apply on Form W-7 with proof of identity and foreign status, normally attached to the tax return itself. Certified Acceptance Agents can verify your documents so you do not have to post your passport.
Do I pay US tax on income from my home country?
If you are a resident for tax purposes, yes — the US taxes worldwide income. That does not necessarily mean paying twice: the foreign tax credit and, where one exists, a tax treaty between the US and your country usually prevent double taxation. Non-residents are taxed only on US-source income.
What is the difference between a W-2 and a 1099?
A W-2 means you were an employee and your employer already withheld tax from each paycheck. A 1099 means you were paid as a contractor with nothing withheld, so you owe income tax plus self-employment tax and may need to pay quarterly estimates. Getting a 1099 when you expected a W-2 is the most common first-year shock.
Do I have to report bank accounts back home?
Possibly. If you are a US person for tax purposes and the combined value of your foreign accounts exceeds $10,000 at any point in the year, you must file an FBAR — a separate filing from your tax return, submitted electronically to the Treasury. Penalties for ignoring it are severe, and it is easy to file.
Primary sources we checked
- IRS — Determining alien tax status
- IRS — Substantial presence test
- IRS — Tax inflation adjustments for tax year 2026
- IRS — Individual Taxpayer Identification Number (Form W-7)
- FinCEN — Report of Foreign Bank and Financial Accounts (FBAR)
- IRS — Free File and free tax preparation help
We link only to the agency or regulator that actually sets the rule. If one of these pages has changed and our guide has not, tell us and we will fix it.
This guide is general information about US federal tax rules, not tax advice, and Fori is not a tax preparer or accountant. Tax outcomes depend on your specific facts, your visa, your state and any treaty between the US and your country. Figures were current at the last update — verify on irs.gov and consider a qualified preparer, a Certified Acceptance Agent, or the IRS free preparation programmes.