For people relocating from Denmark to the United States

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

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

Substantial presenceGreen card testDual-status yearTie-breakerSocial security

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Quick answer

When does someone moving from Denmark 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 Denmark, Article 4 (Residence) 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 (Residence)
Social security agreement: Yes, since October 1, 2008
Accounts in Denmark: FBAR, Form 8938 and PFIC rules can apply once resident

When someone from Denmark becomes a US tax resident

The US decides tax residence with two tests in Code section 7701(b), not by your visa label (IRS Pub 519). Arriving from Denmark, you become a US resident for tax purposes in a year if either applies:

Green card test: you are a lawful permanent resident at any time in the year.
Substantial presence test: at least 31 days in the US this year, and 183 days over three years counting all days this year, one third of last year's and one sixth of the year before.

Count your days with our substantial presence calculator.

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

During the move you can be resident in both Denmark and the US under each country's law. Article 4 (Residence) 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 Denmark, 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).

The residency starting date

Expect your first year to have two halves. Income from Denmark 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 Danish salary, bonuses and investment income the IRS sees.

Accounts left in Denmark

Keeping a Danish bank account or pension after the move is normal, but from your residency starting date the US wants to know about it. The reports are the FBAR, Form 8938 and, for many non-US funds, the PFIC rules on Form 8621 (IRS). Thresholds and deadlines: FBAR and FATCA, Form 8938.

Where these rules come from

Treaty

The IRS lists the 1999 income tax treaty, amended by a 2006 protocol. General effective date (IRS Table 3): treaty Jan. 1, 2001; protocol Jan. 1, 2008 (IRS treaty documents for Denmark; treaty text; IRS Table 3).
Residence and tie-breaker: Article 4 (Residence).
Saving clause: Article 1 (General Scope).
Article 18 (Pensions, Social Security, Annuities, Alimony), pensions.
Article 23 (Relief from Double Taxation), relief from double taxation.
Article 15 (Dependent Personal Services), 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 Denmark on leaving the country also apply; check them with a local adviser.

How we help

We start with your travel dates and your last Danish tax year, work out the residency starting date and whether the treaty tie-breaker applies, then prepare the US return and any Form 8833. Gurleen Kaur, CPA (BC and Washington), signs. You get a written quote first.

Common questions

Does my visa decide my US tax residence after moving from Denmark?

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 Denmark and the US?

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

Do I report my accounts in Denmark 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 Denmark?

Yes, in force since October 1, 2008.

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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