USA: from green card holder to US citizen

Few passports feel as within reach for Germans, and few are as misunderstood, as the American one. Many people think you can buy it, marry into it or apply for it after a few years on a visa. The truth is simpler: there is one single broad road, and it runs through the green card. How the US compares with other countries is covered in the overview Naturalisation abroad. For the US itself, one thing holds: once you have the green card, the hardest part is behind you.

How do you get US citizenship?

There are three ways to a US passport: birth in the US, descent from American parents and naturalisation. For most Germans who were not born in America and have no American parent, naturalisation is the route that remains.

What matters is the difference between a green card and citizenship. The green card makes you a Lawful Permanent Resident: you may live and work in the US permanently, but on conditions. Citizenship, on the other hand, is a right that nobody can take away from you because you spent too long abroad. That is the heart of every second passport: a visa is a permission, a passport is a right. The other reasons for a second passport are set out under Why a second passport.

The first step: the green card

Without a green card, there is no naturalisation on the standard routes. Both of them, the general one and the marriage route, require you to have been lawfully admitted for permanent residence. Years on a temporary visa, say as an investor on an E-2 or as a manager on an L-1, don't count towards naturalisation. The clock only starts on the day you become a permanent resident.

USCIS groups the routes to a green card into categories. For Germans, these are the ones that matter most:

• Family: close relatives of US citizens, including spouses, plus further family categories.
• Employment and achievement: the first to third preference categories, meaning people with extraordinary ability and executives of international companies, professionals with advanced degrees including the National Interest Waiver, and skilled workers.
• Investment: the Immigrant Investors, which USCIS lists among the employment-based routes.
• Diversity Immigrant Visa Program: the green card lottery.

Which of these routes is realistic for you as an entrepreneur or skilled professional, from EB-1 through the National Interest Waiver to EB-5, is explained in US green card: requirements and routes for entrepreneurs.

Keeping the green card

Once the green card arrives, the real discipline begins. USCIS gives a rough rule of thumb: if you stay abroad for more than a year, you risk your permanent residence being treated as abandoned. It can happen even after shorter trips if you no longer treat the US as your permanent home. For longer absences there is the reentry permit, which you apply for before you leave; but after more than two years abroad, even that has expired.

This is exactly where naturalisation shows its worth. As long as you are a green card holder, your life in America depends on your travel dates. As a citizen, it no longer does.

Requirements for US naturalisation

USCIS sets clear conditions for both standard routes, and you must meet them when you apply:

On top of that, the same substantive conditions apply to both routes: you must read, write and speak English, have a basic knowledge of American history and civics, show good moral character and be attached to the principles of the Constitution. At the end, you take the Oath of Allegiance.

Good moral character is assessed for the five years before you file, or for the three years before filing on the marriage route. Anything that touches on your conduct in that period therefore needs to be on the table before you submit. What USCIS understands by it in detail today is covered in US naturalisation: the good moral character test.

Five years, 30 months: how USCIS counts your time

The deadlines sound simple, but this is exactly where the traps lie. Two clocks run side by side, and both have to add up.

Continuous residence

The first clock is continuous residence. Not every trip breaks it, but long ones do. The USCIS Policy Manual distinguishes two cases:

1. Absence of more than six months but less than a year: continuous residence is presumed to be broken. You can rebut that presumption, for example by showing that you kept your job in the US and did not work abroad, that your immediate family stayed in the country and that your home in the US remained available to you.
2. Absence of a year or more: continuous residence is broken automatically. Without an approved Form N-470, USCIS must deny the application and your clock starts again from zero.

There is an exception for certain green card holders who work abroad for the US government, for American companies, for international organisations or for religious organisations. If you fall into that group, you preserve your residence with Form N-470. The condition: you were physically in the US as a green card holder for at least one uninterrupted year beforehand, and you file before you have spent a full year abroad in one stretch.

Physical presence

The second clock is physical presence. On the general route, you must have actually been in the US for at least 30 months during the five years before you file, so at least half the time. On the marriage route, it's 18 months in three years.

So if you travel a lot, you can keep the first clock running and still fail on the second: lots of trips of four or five months don't break continuous residence, but they quickly add up to more than half the time. That's why you should keep a travel log of every entry and exit date from the first day you hold a green card. How other countries count residence time is shown in the overview Naturalisation abroad.

Filing early

The law offers one small concession: under 8 U.S.C. 1445(a), you may file up to three months before the day you meet the residence requirement. All the other requirements must still be met at that point.

Applying for US citizenship: N-400, interview and oath

The application for naturalisation is called Form N-400, Application for Naturalization. The process is the same for everyone:

1. Check your timelines: document your green card years, residence and presence with your travel log.
2. File the application: submit Form N-400 online or on paper and pay the fee.
3. Biometrics: you usually give fingerprints and a photo at an appointment, unless USCIS waives it.
4. Interview: a USCIS officer goes through your application with you, in English. At the same appointment you take the English test and the civics test.
5. Ceremony and oath: you only become a US citizen when you take the Oath of Allegiance at a naturalisation ceremony. Sometimes that's possible on the day of the interview; otherwise the invitation arrives by post with Form N-445.
6. Apply for your passport: after the oath you receive your Certificate of Naturalization, and your welcome packet includes an application form for a US passport.

The details of the form, the documents and the interview are covered in US citizenship: requirements and Form N-400. USCIS advises leaving enough time for the passport between the ceremony and your next planned trip.

The US citizenship test: English and 128 questions

The test has two parts, and both take place during the interview.

English: the officer assesses your spoken English as you talk through your application. You also read one of three sentences correctly and write one of three sentences correctly. For Germans with school English, this is rarely a hurdle.

Civics: for applications filed on or after 20 October 2025, the 2025 test applies. It's oral: the officer asks you 20 questions from a public list of 128 on history, the Constitution and how government works. With 12 correct answers you pass; with 9 wrong ones you fail. If you filed earlier, you still take the 2008 test.

You get two attempts. If you fail one part at your first interview, you are retested on that part 60-90 days later. Because USCIS publishes the list of questions together with the answers, you can prepare in a targeted way. How the tests in Canada, the UK, Switzerland and Spain compare is shown in Language, test, oath.

How much does US naturalisation cost?

The government fee is modest, measured against what you get for it:

The real price of US citizenship isn't on any fee schedule. It lies in the years until the green card and the five years after it, during which you plan your trips and keep your residence.

Buying US citizenship: is it possible?

Hardly any question comes up more often, and the answer is clear: no. US law has no citizenship by investment. Even the investor routes that USCIS lists among the green card categories end at the green card. After that, investors face the same five years, the same 30 months and the same test as everyone else.

Money can speed up the first step, then, but not the second. What the Gold Card and EB-5 really deliver, and how long the road takes with them, is shown in Can you buy a US passport? Gold Card, EB-5 and the realistic route.

If you're looking for a passport through investment, you'll find it elsewhere, and in months rather than years. Sierra Leone, for example, usually issues the passport 90-120 days after the complete application; all the details are under Sierra Leone. The other open programmes, with figures and timelines, are listed under Programmes and side by side in the comparison.

Dual citizenship: become American, stay German

In the Oath of Allegiance, you renounce all allegiance to any foreign state of which you have been a citizen. That sounds like the end of your German passport. Under German law, it no longer is.

Since 27 June 2024, acquiring a foreign nationality on application no longer means losing your German one. The former retention permit (Beibehaltungsgenehmigung) has been abolished. If you naturalise in the US today, you stay German and hold two of the most important passports in the world.

The reform has one limitation: it does not apply retroactively. Anyone who became American before 27 June 2024 without a retention permit lost German citizenship under the old law. According to the German Federal Foreign Office, they may be able to regain it by naturalisation under the conditions of Section 13 of the Nationality Act (Staatsangehörigkeitsgesetz, StAG).

Which passport you use to enter the US as a dual citizen, and what two nationalities mean for travel, taxes, military service and children, is covered in detail in German and US dual citizenship.

Pros and cons of US citizenship

Naturalisation changes more than a document. It changes what you are entitled to and what you owe.

The biggest advantage: the right to stay

As a green card holder, you live with a permission. As a citizen, you have a right. You can spend a year in Germany, look after your parents, work abroad and still come back at any time, without an officer questioning your status.

Children: a passport for the next generation

When you naturalise, your children come with you. Under 8 U.S.C. 1431, a child born outside the US automatically becomes a US citizen if one parent is a US citizen, the child is under 18 and lives in the US with a green card in that parent's legal and physical custody. No separate Form N-400 is needed. What applies to children born in the US is explained in Child born in the US. How to plan passports for the whole family is shown on the Family page.

The drawback everyone should know about: taxes

The US taxes its citizens on their worldwide income, wherever they live. The Internal Revenue Service puts it plainly: US citizens and residents abroad are subject to tax on their worldwide income from all sources. Relief comes through the Foreign Earned Income Exclusion and the Foreign Tax Credit, but only if you file a US tax return.

As long as you live in the US, naturalisation changes little here, because residents also pay tax on their worldwide income. The difference shows when you leave the US again: as a citizen, you take your US tax liability with you wherever you move. What dual citizens owe the IRS and the German tax office every year is explained in US dual citizenship: taxes on both sides. How residence and nationality interact for tax purposes is shown on the Taxes page.

Securing the years until your US passport

Be honest with the numbers: getting a green card often takes years, then at least five more follow, or three at best with a US spouse. During that time your plan depends on conditions you don't fully control: categories, waiting lists, days travelled and whether your life over the coming years really plays out in America.

That's why it pays not to choose, but to combine. Naturalisation is the affordable route and, in the end, the strongest, but it needs time and genuine residence. Citizenship by investment buys you exactly that time: a second right within months, regardless of how your path in the US unfolds. Why the two routes belong together is explained in CBI and naturalisation.

The result is a plan in two stages. Today, a second passport that gives you freedom of movement and security in case the green card wobbles or life calls you back to Europe for a while. Tomorrow, the American passport, once the years are complete. And through both stages, your German passport stays in your drawer.

Frequently asked questions