I'm married to a non-US citizen. What is my filing threshold?
If you file Married Filing Separately, which is the default when your spouse is a nonresident alien and you make no election, the 2025 gross-income filing threshold is $5 at any age, not the $15,750 that applies to a single filer. You cannot use Single filing status while married. Head of Household is available only if you meet its own test. Separately, the FBAR and Form 8938 have their own triggers that ignore your filing threshold entirely.
The number is $5, and it is not a typo
For 2025 the gross-income filing threshold for Married Filing Separately is $5, at any age. The IRS states it that way, without conditions, in Chart A of the Form 1040 instructions.
It is a gross income figure. Not profit, not taxable income, not income after the exclusion. You can be required to file and owe nothing.
Most people meet this rule the moment they marry a non-US citizen, because MFS is what you get by default.
Why marrying a nonresident alien puts you there
Your filing status is not a preference. Once married, Single is not available to you, whatever your spouse's citizenship. That leaves three possibilities.
Married Filing Separately is the default when your spouse is a nonresident alien and you make no election. You report your own income, and your spouse's foreign income generally stays off your return. Community property is the exception worth knowing about: where you live under a community property regime, section 879 allocates community income between the spouses under its own rules rather than leaving all of it out. That is a statement about your return, not about their obligations: a nonresident alien spouse with US-source income, or engaged in a US trade or business, can have a Form 1040-NR requirement of their own. This is where the $5 threshold applies.
Married Filing Jointly requires an election under section 6013(g) to treat your nonresident spouse as a US resident for tax purposes. It is a joint choice, it needs a signed statement attached to the return, your spouse needs an SSN or ITIN, and it puts their worldwide income on your US return. It generally stays in force until revoked.
Head of Household works differently here than it does for other married people. If your spouse was a nonresident alien at any time in the year and you have not elected to treat them as a US resident, you are considered unmarried for Head of Household purposes, so the usual requirement to live apart for the last six months does not apply to you. The other tests still do: you must have paid more than half the cost of keeping up your home, and you must have a qualifying person. That is usually someone who lived with you for more than half the year, though a dependent parent can qualify while living elsewhere if you paid more than half the cost of keeping up their main home. Your nonresident spouse is not that person. Being married to a nonresident alien does not by itself qualify you.
So the common path is MFS, and the common surprise is the threshold that comes with it.
Where the $5 actually comes from
The usual explanation you will find is that it follows from the rule that a spouse who itemizes forces the other spouse out of the standard deduction. That rule is real, at section 63(c)(6), but it is not what produces this number.
Section 6012(a)(1)(A) is the filing-requirement rule. It sets standard-deduction-based exceptions for single filers, heads of household, surviving spouses and joint filers. Married Filing Separately is not on that list. With no exception available, the general rule applies: file when gross income reaches the exemption amount. The exemption amount is currently zero, and the IRS publishes the threshold as $5.
The practical consequence is the same either way. The reason matters if you are trying to work out whether some other fact changes it. It does not.
Three tests, not one
The filing threshold is one obligation. Two more run on their own rules and do not care what your threshold is.
FBAR (FinCEN Form 114) is required when the aggregate maximum value of your foreign financial accounts is more than $10,000 at any point in the calendar year. That covers accounts you have a financial interest in and accounts over which you have signature or other authority. It is filed with FinCEN, not the IRS, and it is not part of your return.
Form 8938 applies when you are required to file an income-tax return and your specified foreign financial assets are over the applicable threshold. Living abroad and not filing jointly, that is more than $200,000 at year-end or more than $300,000 at any time; filing jointly, more than $400,000 or $600,000 respectively.
A year where you earn almost nothing can still carry all three obligations.
What this does not mean
It does not mean you owe US tax. The Foreign Earned Income Exclusion and the Foreign Tax Credit are claimed on a filed return, and for many people abroad they reduce the bill substantially. Whether they reduce it to zero is a return calculation that depends on your own facts.
It also does not mean MFS is the wrong choice. The section 6013(g) election has real consequences of its own, including putting a nonresident spouse's worldwide income into the US system. Which status serves you better is a question about your specific numbers.
Nothing here is legal or tax advice about your situation.
Reference information, not legal or tax advice. Figures come from our verified fact base and are checked against superseded values on every site update.