This article covers the return filed during the 2026 filing season, which is for tax year 2025. Tax year 2026 returns are filed in 2027, and the IRS's 2026 Form 1040 is still marked "DRAFT - DO NOT FILE," so recheck the final form before relying on it.
The checkbox is not a citizenship test or a tax-residency test. It's a factual question about where you lived.
Key Takeaways
- The box asks if your main home (and your spouse's, on a joint return) was in the U.S. for over half of 2025.
- Joint filers must test both spouses' homes before checking it.
- U.S. citizens and green card holders in Australia may still have to file, even with the box unchecked.
- Review credits separately and get professional help when foreign income is involved.
What Does "Check Here If Your Main Home" Mean on Form 1040?
The 2025 form reads: "Check here if your main home, and your spouse's if filing a joint return, was in the U.S. for more than half of 2025." It sits beside the address block and has no line number, according to the 2025 Form 1040. It doesn't appear on the 2024 form.
How the IRS defines a main home
Per the 2025 instructions, your main home is where you regularly lived. It can be a house, apartment, mobile home, shelter or temporary lodging, and it needn't be the same place all year. Owning a property, or using a U.S. mailing address, doesn't make it your main home.
Temporary absences for school, vacation, business, medical care or military service can count as time lived at home. The instructions also treat military members on extended active duty abroad (an indefinite period or more than 90 days) as having a U.S. main home.
What the box is not
It isn't a citizenship question or an immigration-status question. It doesn't replace the green card or substantial presence tests that decide resident-alien status, which Publication 519 describes. U.S. citizens and resident aliens generally report worldwide income wherever they live.
Three quick scenarios
- Stayed in the U.S. all year: Main home was in the U.S., so the box is checked.
- Lived in Melbourne all year: Main home was in Australia, so leave it blank. You may still need to file.
- Moved mid-year: The instructions say a main home can be in more than one place during the year. Count the months in the U.S. and check only if they exceed half the year.
How to Decide Whether to Check the Box
For single filers
Work through it in order:
- Confirm the tax year (2025 for the 2026 season).
- Work out where you regularly lived, month by month.
- Check whether the U.S. months total more than half the year.
- Compare your facts with the official instructions.
A U.S. passport, bank account, mailing address or rental property doesn't prove a U.S. main home.
For married couples filing jointly
The checkbox wording covers both spouses. The instructions give no example for spouses who lived in different countries, so don't assume one spouse's U.S. home is enough.
If one spouse lived in Sydney and the other in Texas, or you kept homes in both countries, get advice before ticking it.
For taxpayers living in Australia
A U.S.-connected taxpayer in Australia can have a Form 1040 obligation with no U.S. main home. The filing threshold counts income that may later be excluded.
For 2025 it's $15,750 for a single filer under 65 and $31,500 for joint filers both under 65, per the 2025 Form 1040 instructions.
The checkbox is separate from other regimes:
- Foreign earned income exclusion: Claimed on Form 2555 (maximum $130,000 for 2025).
- Foreign tax credit: Generally claimed on Form 1116.
- FBAR: Filed separately with FinCEN if foreign accounts exceeded $10,000 in aggregate at any point.
- Form 8938: Attached to the return, with higher thresholds for those living abroad.
Whether Australian superannuation is reportable on Form 8938 isn't settled by the instructions, so ask a professional.
Build a timeline before filing. Leases, utility bills, travel calendars and school or medical records all help establish where you lived. The Form 1040 instructions don't require any particular proof for this box.
Why the Main-Home Checkbox Matters for Tax Credits
The IRS uses the answer as a data point for the earned income tax credit (EITC). Under Publication 596, a taxpayer with no qualifying child generally needs a U.S. main home for more than half the year.
With a qualifying child, the child must have lived with you in the U.S. for more than half the year. The U.S. here means the 50 states and D.C.
Checking the box doesn't qualify you for anything. Income, filing status, child rules and Social Security numbers all apply separately. Anyone who files Form 2555 can't claim the EITC.
Don't check the box just to chase a refund. The IRS can disallow the EITC for two years for reckless disregard of the rules and ten years for fraud, but those aren't automatic results of a checkbox mistake.
If you got it wrong
- Left blank or checked in error: Review the whole return with a professional.
- Amending: File Form 1040-X. A refund claim is generally due within three years of filing or two years of paying tax, whichever is later.
- IRS notice: Follow its directions exactly.
A "No" answer never means you needn't file. It also says nothing about the foreign tax credit or exclusion. Foreign tax credits work by crediting tax paid to a foreign government against your liability.
Other Form 1040 Changes to Review for the 2026 Filing Season
Keep the years straight. A return filed in spring 2026 covers 2025. The 2026 inflation adjustments generally apply to returns filed in 2027.
Confirmed changes on the 2025 return include:
Schedule 1-A adds new deductions with income phaseouts:
Qualified tips: up to $25,000
Overtime: up to $12,500 ($25,000 jointly)
Car loan interest: up to $10,000
Senior deduction: up to $6,000 per person
Standard deduction (2025): $15,750 single, $31,500 joint, $23,625 head of household
Instruction updates: IRS clarifications posted April 7, 2026; see the change page
For tax year 2026, the standard deduction rises to $16,100 single and $32,200 joint. Don't use those figures on a 2025 return.
Software may place the residency question in an interview flow. Review the finished return rather than trusting default answers.
Filing Checklist for Taxpayers in Australia
- Confirm the tax year and the correct Form 1040 version.
- Build a timeline of where you and your spouse lived.
- Convert Australian income to U.S. dollars using IRS-accepted exchange rates.
- Review filing status, foreign wages or business income, Australian tax paid and credits.
- Check FBAR and Form 8938 triggers.
- Note the automatic extension to June 15 for those whose tax home and abode are abroad. Interest still runs from April.
The U.S.-Australia treaty has a saving clause that lets the U.S. generally tax its citizens as if the treaty weren't in force, so don't assume treaty relief.
VJM Global provides tax, accounting, compliance and advisory support for international clients, including U.S. Form 1040 preparation. Its team includes CPAs and U.S.-compliant professionals.
If you run an Australian business or cross-border operation that raises personal U.S. tax questions, a qualified tax professional should review your specific position.
Frequently Asked Questions
What is considered a tax resident?
It depends on each country's rules, using facts such as citizenship, immigration status, physical presence, domicile or treaty terms. The ATO's tests, for example, are the resides, domicile, 183-day and Commonwealth superannuation tests. The checkbox is not a residency test.
What is a basic 1040?
Form 1040 is the main U.S. individual federal income tax return. Schedules and forms may be added for foreign income, business income, credits, deductions or financial accounts.
Is the main home checkbox the same as tax residency?
No. It's a separate factual question about where your main home was for the year. Citizenship, green card status, substantial presence and treaty residency follow different rules.
Do U.S. citizens living in Australia check the main home box?
Only if their main home was in the U.S. for more than half the year. Citizenship, or the duty to file, doesn't decide it.
What should married couples filing jointly do with the main home checkbox?
Read the wording for both spouses and count time in the U.S. and Australia. Check the box only if the facts meet the requirement, and seek advice if the spouses lived apart.
