The expat tax filing threshold is the same gross income figure that applies to Americans at home. For the 2025 tax year it is $15,750 for a single filer under 65, $31,500 for a married couple filing jointly, and just $5 if you are married filing separately. Income you plan to exclude under the foreign earned income exclusion still counts toward these figures.
That last point catches many Americans abroad. They earn less than the $130,000 foreign earned income exclusion, owe no US tax, and assume they have nothing to file. In fact, the exclusion is only available on a filed return, so a person earning £40,000 in London owes nothing but must still file. This guide sets out the 2025 and 2026 thresholds, the traps for expats, and what happens if you have missed years.
How the expat tax filing threshold works
US citizens and green card holders are taxed on worldwide income wherever they live. Consequently, the filing requirement in Internal Revenue Code section 6012 applies to you in London, Dubai or anywhere else, exactly as it would in Ohio. The test looks at your gross income, your filing status and your age.
The expat tax filing threshold for 2025 and 2026
The thresholds broadly track the standard deduction. The 2025 figures apply to the return you file in 2026, and the 2026 figures, set by the IRS in Revenue Procedure 2025-32, apply to the return you file in 2027.
| Filing status (under 65) | 2025 gross income threshold | 2026 standard deduction (IRS Rev. Proc. 2025-32) |
|---|---|---|
| Single | $15,750 | $16,100 |
| Married filing jointly | $31,500 | $32,200 |
| Head of household | $23,625 | $24,150 |
| Married filing separately | $5 | $5 threshold applies regardless |
| Net self-employment earnings (any status) | $400 | $400 |
Higher thresholds apply if you or your spouse are 65 or older, as set out in the Form 1040 instructions. Additionally, the IRS 2026 inflation adjustment release confirms the 2026 figures and the new $132,900 foreign earned income exclusion.
What counts as gross income
Gross income means all worldwide income before exclusions and deductions. It includes foreign salary, UK self-employment profits, interest, dividends, rental receipts and capital gains. IRS Publication 54 confirms that you must include income you could exclude under the foreign earned income exclusion when deciding whether you need to file.
Why the foreign earned income exclusion does not remove the duty to file
The foreign earned income exclusion under section 911 is an election, not an automatic exemption. You claim it on Form 2555, attached to Form 1040. Therefore, if you do not file, you have not claimed it, and the income is technically taxable.
Late claims are possible but limited
Treasury Regulation section 1.911-7 generally lets you make the election on a late return filed within one year of the original due date. After that, you can still claim it if you owe no federal income tax after the exclusion, or if you file before the IRS discovers that you failed to elect. Accordingly, filing late is usually safer than not filing at all.
An illustrative example
Take an illustrative single American teacher in Manchester who earns £38,000, about $50,000. That income is well over the $15,750 threshold, so a 2025 return is required. However, after the exclusion or a foreign tax credit for UK income tax, little or no US tax is likely to be due. The return costs effort, not tax, but skipping it removes the protection.
The $5 trap for Americans married to non-US citizens
The married filing separately threshold is the most common reason a low-earning expat must file. If you are married to a non-US citizen and do not elect to treat them as a US resident, you normally file as married filing separately. In that case, gross income of just $5 triggers the requirement.
Head of household as an alternative
A US citizen married to a nonresident alien can sometimes file as head of household if they have a qualifying child or dependant living with them. That raises both the threshold and the standard deduction. Our guide to filing when married to a non-US citizen compares the options, including the section 6013(g) election to file jointly.
Why the threshold rarely helps couples abroad
In practice, almost any working American married to a British or Emirati spouse will exceed $5 of income. As a result, the useful question is not whether to file, but which filing status and which relief produce the lowest US tax.
Self-employed expats and the $400 rule
If you have net self-employment earnings of $400 or more, you must file regardless of your total income. This rule applies to UK sole traders, freelancers in Dubai and online consultants anywhere.
The US-UK totalization agreement
The US-UK totalization agreement stops you paying both US self-employment tax and UK National Insurance on the same earnings. For a UK resident who is self-employed, UK National Insurance usually applies instead. However, you claim the US exemption on your return, generally supported by a certificate of coverage from HMRC. Our guide to the US-UK totalization agreement explains the certificate process.
No agreement with the UAE
There is no US totalization agreement with the UAE. Consequently, a self-employed American in Dubai generally owes US self-employment tax of 15.3% on net earnings, up to the Social Security wage base, even though the foreign earned income exclusion removes income tax. The exclusion does not reduce self-employment tax.
Other reasons to file even under the threshold
Sometimes filing is worthwhile even when it is not required. For example, the refundable portion of the child tax credit can produce a payment for lower-income expats with qualifying children, but only if you file. Similarly, filing starts the three-year statute of limitations on assessment, which never begins on an unfiled year.
Information returns have their own thresholds
The income threshold does not affect foreign account reporting. The FBAR, FinCEN Form 114, is required if your foreign accounts together exceeded $10,000 at any time in the year, according to FinCEN. Form 8938 has separate, higher thresholds for taxpayers living abroad. Our FBAR and FATCA reporting guide covers both.
Deadlines and catching up on missed years
For the 2025 tax year, the return is due on 15 April 2026. Americans living abroad on that date get an automatic two-month extension to 15 June 2026, and Form 4868 extends further to 15 October 2026. Our guide to US expat tax deadlines sets out every date.
If you have never filed
If you exceeded the threshold in past years and did not file, the IRS Streamlined Foreign Offshore Procedures let non-willful expats catch up with three years of returns and six years of FBARs, generally with no penalty. In our experience, most expats who come to us for catch-up filing owe little or no tax once exclusions and credits are applied.
Frequently Asked Questions
Do I have to file US taxes if I live abroad and earn under the foreign earned income exclusion?
Yes, you must file a US tax return if your worldwide gross income exceeds the filing threshold, even if all of it is covered by the foreign earned income exclusion. The exclusion only applies when you claim it on Form 2555 with a filed Form 1040. For 2025, the single threshold is $15,750.
What is the US expat tax filing threshold for 2025?
The US expat tax filing threshold for 2025 is $15,750 for single filers under 65, $31,500 for married couples filing jointly, $23,625 for heads of household and $5 for married filing separately. Net self-employment earnings of $400 or more also require a return. These figures apply to the return filed in 2026.
Does foreign income count toward the US filing requirement?
Yes, foreign income counts toward the US filing requirement. IRS Publication 54 states that gross income for this test includes all worldwide income, including income you could exclude under the foreign earned income exclusion. UK salary, UAE salary, foreign interest and foreign rental income all count.
Why is the filing threshold only $5 for Americans married to foreigners?
The filing threshold is $5 for married filing separately, which is the usual status for a US citizen married to a nonresident alien. The figure comes from the filing rules in the Form 1040 instructions and is not inflation-adjusted, so almost any income triggers a return. Electing to file jointly under section 6013(g), or qualifying as head of household, gives a higher threshold.
Do self-employed Americans in the UK have to file a US return?
Yes, a self-employed American in the UK with net self-employment earnings of $400 or more must file a US return. Under the US-UK totalization agreement, UK National Insurance usually replaces US self-employment tax, but the exemption is claimed on the US return. A certificate of coverage from HMRC supports the claim.
What happens if I did not file because I thought I was under the threshold?
If you exceeded the threshold but did not file, you can usually catch up through the IRS Streamlined Foreign Offshore Procedures if the failure was non-willful. The procedures require three years of returns and six years of FBARs, generally with no penalty. Most expats in this position owe little or no US tax after exclusions and credits.
Not sure whether you need to file?
The threshold is simple, but the filing status, exclusion and credit choices that follow are not. If you are living in the UK or UAE and unsure whether you should have filed, book a consultation with Tranzesta. We will confirm your filing position for each year and the lowest-tax way to bring you up to date.
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