For people relocating from Belgium to the United States

Moving to the US From Belgium: Your First US Tax Year

Before your first US tax return after leaving Belgium, three questions matter: when you became resident, whether the treaty makes you resident somewhere else, and what to report from Belgium.

Substantial presenceGreen card testDual-status yearTie-breakerSocial security

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Quick answer

When does someone moving from Belgium start paying US tax on worldwide income?

From the residency starting date: the first day in the US in a year you meet the substantial presence test, or the first day as a permanent resident under the green card test (IRS Pub 519). Before that you are a nonresident, so the first year is usually dual-status. If you are also resident in Belgium, Article 4 (Resident) of the treaty decides which country you are resident in for treaty purposes.

Prepared by Illuminous Accounting · Sources checked November 11, 2026

At a glance

When you become US resident: Green card test or substantial presence test (Code section 7701(b))
First year: Usually dual-status: nonresident, then resident
Treaty tie-breaker: Article 4 (Resident)
Social security agreement: Yes, since July 1, 1984
Accounts in Belgium: FBAR, Form 8938 and PFIC rules can apply once resident

Arriving from Belgium: which test applies

There is no form that makes you a US tax resident. It happens automatically under Code section 7701(b) once you pass either test (IRS Pub 519). A green card does it from the first day you are in the US with permanent resident status. Without one, the substantial presence test does it once you have 31 days this year and 183 weighted days over three years.

Someone arriving from Belgium with no earlier US days needs to arrive by early July and stay for the rest of the year to pass the substantial presence test in the first year. The calculator shows the date for your arrival.

The residency starting date

Expect your first year to have two halves. Income from Belgium before you became resident is generally outside US tax unless it is US-source; income after the residency starting date is taxed worldwide (IRS Pub 519). The starting date is your first day in the US in that year under the substantial presence test, or your first day as a permanent resident under the green card test. People who arrive near year end may be able to opt in early under the first-year choice. Getting the date right decides which Belgian salary, bonuses and investment income the IRS sees.

Resident in both countries: the US-Belgium treaty tie-breaker

During the move you can be resident in both Belgium and the US under each country's law. Article 4 (Resident) of the treaty has the tie-breaker for someone resident in both countries: it looks first at where you have a permanent home available, then at the further tests the article lists, in the order it sets them. If the treaty makes you a resident of Belgium, you can be taxed as a nonresident of the US for the treaty's purposes, but that position must be disclosed on Form 8833 under Treas. Reg. section 301.7701(b)-7 (IRS Form 8833).

Green card holders should be careful: a long-term resident who claims treaty residence abroad this way may be treated as having expatriated under section 877A (IRS).

Reporting what you keep abroad

Do not close everything in Belgium in a hurry, and do not forget it either. As a US resident you report foreign accounts on the FBAR and Form 8938 when they pass the thresholds, and many investment funds bought in Belgium fall under the PFIC rules (IRS). Details: FBAR and FATCA; Form 8938.

Where these rules come from

Treaty

The IRS lists the 2006 income tax treaty, amended by a protocol listed for 2006. General effective date (IRS Table 3): treaty Jan. 1, 2008 (IRS treaty documents for Belgium; treaty text; IRS Table 3).
Residence and tie-breaker: Article 4 (Resident).
Saving clause: paragraph 4 of Article 1 (General Scope).
Article 17 (Pensions, Social Security, Annuities), pensions.
Article 22 (Relief From Double Taxation), relief from double taxation.
Article 14 (Income From Employment), employment income.

US law

US residency tests and starting dates: Code section 7701(b) (IRS Pub 519).
Treaty residence for dual residents: Treas. Reg. section 301.7701(b)-7, Form 8833 and section 6114; long-term residents: section 877A (IRS Form 8833).
Social security agreements: SSA list.

The rules of Belgium on leaving the country also apply; check them with a local adviser.

How we help

Gurleen Kaur, CPA licensed in British Columbia and Washington State, prepares the first-year dual-status return, treaty disclosures and the reporting for accounts left in Belgium. Every engagement starts with a written quote after we review your dates and income. Also see Form 1040-NR.

Common questions

When do I become a US tax resident after moving from Belgium?

When you meet the green card test or the substantial presence test (31 days this year and 183 weighted days over three years). Your residency starting date is generally your first day in the US that year, or your first day as a permanent resident.

What if I am resident in both Belgium and the US?

Article 4 (Resident) of the treaty breaks the tie, starting with where you have a permanent home. Claiming treaty residence in Belgium on a US return needs Form 8833.

Do I report my accounts in Belgium after moving to the US?

Once you are a US resident, yes: the FBAR when foreign accounts total more than US$10,000, Form 8938 above higher thresholds, and PFIC rules for many foreign funds.

Is there a US social security agreement with Belgium?

Yes, in force since July 1, 1984.

Sources

Every rule and figure on this page links to the IRS, CRA or other official source it comes from. Amounts change; we re-check them before each engagement.

Gurleen Kaur, CPA licensed in British Columbia and Washington State. Last updated November 11, 2026. This page is general information, not tax or legal advice for your situation.

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