Naturalization Explained: Your Complete N-400 Guide

If you're a green card holder thinking about becoming a U.S. citizen, you're probably wondering where to start. The process has a name: naturalization. It's how millions of immigrants have officially become Americans, and it begins with one form: the N-400.

This guide breaks down everything you need to know. I'll walk you through who qualifies, what it costs, how long it takes, and what happens at each step. You'll also learn about the 2025 civics test changes that took effect in October, so you know exactly what to expect.

Whether you've had your green card for a few years or you're just starting to think about citizenship, this resource will help you understand the full picture before you file. No legal jargon, no confusion. Just the facts in plain English.

What Is Naturalization?

Naturalization is the legal process that allows immigrants to become U.S. citizens. If you weren't born a citizen (either by birth in the U.S. or through U.S. citizen parents), naturalization is how you get there.

Here's the key distinction: citizenship is a status, but naturalization is the process of earning that status. When someone says they're a "naturalized citizen," it means they went through this process and took the Oath of Allegiance.

The process involves filing an application with U.S. Citizenship and Immigration Services (USCIS), attending a biometrics appointment, passing an interview and citizenship test, and finally taking the Oath of Allegiance at a naturalization ceremony. Once you complete that oath, you're officially a U.S. citizen with all the rights and responsibilities that come with it.

Why do people pursue naturalization? The benefits are significant. Citizens can vote in federal elections, hold certain government jobs, sponsor more relatives for immigration, travel with a U.S. passport, and never worry about deportation again. There's also something deeply meaningful about fully belonging to the country you've made your home.

Who Can Apply for Citizenship?

Not everyone with a green card can apply right away. USCIS has specific eligibility requirements based on how long you've had your green card and your circumstances.

The 5-Year Path (General Eligibility)

Most green card holders follow this path. You can apply for naturalization after holding your green card for at least 5 years. During those 5 years, you must have been physically present in the U.S. for at least 30 months (that's 913 days) and maintained continuous residence.

You can actually file your N-400 up to 90 days before you hit the 5-year mark, which helps you get ahead in line while still meeting the requirement by the time of your interview.

The 3-Year Path (Marriage to U.S. Citizen)

If you're married to a U.S. citizen and got your green card through that marriage, you may qualify for a faster track. You can apply after just 3 years as a permanent resident, as long as you've been living with your U.S. citizen spouse during that entire time.

For this path, you need to have been physically present in the U.S. for at least 18 months out of those 3 years. Your spouse must have been a U.S. citizen for at least 3 years as well.

Military Service Paths

Active-duty members of the U.S. military and veterans have special naturalization options. If you've served honorably for at least one year during peacetime, you may be able to apply while still serving or within 6 months of leaving the military, with no specific residency requirement.

Those who served during designated periods of hostility (the "War on Terrorism" period starting September 11, 2001, for example) may be able to naturalize immediately, even without a green card.

Pro tip: Use the USCIS Naturalization Eligibility Tool to check if you meet the requirements before you start your application.

N-400 Requirements You Must Meet

Beyond the residency timelines, USCIS requires all naturalization applicants to meet these additional requirements:

Age: You must be at least 18 years old to file Form N-400.

Continuous residence: You must have lived continuously in the U.S. as a green card holder for the required period (3 or 5 years). Extended trips outside the U.S. (6 months or longer) can break this continuity and require you to start over. Learn more about the physical presence requirement before you apply.

Physical presence: You must have been physically present in the U.S. for at least 30 months out of 5 years (or 18 months out of 3 years for the marriage-based path). This isn't the same as continuous residence. Every day spent outside the U.S. counts against your physical presence total.

State residency: You must have lived in the state (or USCIS district) where you're applying for at least 3 months before filing.

Good moral character: USCIS evaluates whether you've demonstrated good moral character during the statutory period. Certain criminal convictions, lying on immigration applications, failing to pay child support, or not registering with Selective Service (for males 18-25) can affect this determination.

English and civics knowledge: You must demonstrate the ability to read, write, and speak basic English. You also need to pass a civics test covering U.S. history and government.

Attachment to the Constitution: You must be willing to support and defend the U.S. Constitution and take the Oath of Allegiance.

How Much Does Naturalization Cost in 2025?

The government filing fee for Form N-400 depends on how you submit your application:

The fee includes biometrics processing. There's no longer a separate fingerprinting fee.

Important change: As of October 28, 2025, USCIS no longer accepts checks, money orders, or cashier's checks for paper filings. You must pay using Form G-1450 (credit/debit card) or Form G-1650 (ACH bank transfer). If you file online, you can pay directly through your USCIS account. Read more about how to pay USCIS filing fees.

Fee waiver: If your household income is at or below 150% of the Federal Poverty Guidelines, you may qualify for a complete fee waiver using Form I-912.

Reduced fee: If your income is between 150% and 400% of the Federal Poverty Guidelines, you may qualify for the reduced $380 fee.

If you're requesting a fee waiver or reduced fee, you must file a paper application. Online filing isn't available for these requests.

Note: Military members applying based on qualifying service are exempt from the filing fee.

The Naturalization Process: Step by Step

Here's what happens after you decide to apply for citizenship:

Step 1: File Form N-400

The process starts when you submit Form N-400, Application for Naturalization, along with the filing fee and required supporting documents. You can file online through your USCIS account or mail a paper application to the appropriate USCIS lockbox.

Required documents typically include a copy of your green card (front and back), two passport-style photos (if filing from abroad), and any evidence specific to your eligibility category.

After USCIS receives your application, they'll send you a receipt notice (Form I-797C) within 2-4 weeks. This receipt extends your green card validity for 24 months, which matters if your card expires while your application is pending.

Step 2: Biometrics Appointment

About 3-8 weeks after filing, USCIS will mail you an appointment notice for biometrics. This is a short appointment (usually under 20 minutes) at a local Application Support Center where they collect your fingerprints, photograph, and signature for background checks.

Bring your appointment notice, your green card, and a photo ID. Try not to reschedule this appointment. Doing so can add weeks to your processing time.

Good news for some applicants: USCIS may reuse biometrics from a previous immigration application if they're still valid. If this applies to you, you won't receive a biometrics appointment notice at all. Your case will simply move forward to the interview stage. This is more common for people who recently filed other applications (like I-751 to remove conditions) and already have their fingerprints on file.

Step 3: Citizenship Interview and Exam

The interview is the most important step. A USCIS officer will review your application with you, verify your answers, and test your English and civics knowledge.

For the English test, the officer will ask you to read a sentence aloud and write a sentence they dictate. The civics test is oral. The officer asks questions about U.S. history and government from a list of possible questions.

If you pass the interview and exam, the officer may approve your application on the spot. In some cases, USCIS may request additional documents or schedule a second interview.

If you don't pass, you get one more chance to retake the portion you failed at a later date.

Step 4: Oath of Allegiance Ceremony

You're not a citizen until you take the Oath of Allegiance. After your application is approved, USCIS will schedule you for a naturalization ceremony. This might happen the same day as your interview or weeks later, depending on your field office.

At the ceremony, you'll return your green card, take the oath, and receive your Certificate of Naturalization. That certificate is your proof of citizenship. Check it carefully for errors before you leave.

The 2025 Citizenship Test: What's Changed

If you file your N-400 on or after October 20, 2025, you'll take the new 2025 Naturalization Civics Test. This test is more challenging than the previous version.

The 2025 test draws from a pool of 128 possible questions, up from 100. During your interview, the officer asks up to 20 questions. You need 12 correct answers to pass. The officer stops asking questions once you reach either 12 correct or 9 incorrect.

About 75% of the content comes from the previous test, but there are new questions and some changes in wording and focus. The 2025 test places more emphasis on U.S. history and governance and less on geography.

Special exception: Applicants who are 65 or older and have been permanent residents for at least 20 years can take a simplified test with 10 questions (6 correct to pass) from a designated set of 20 questions. They may also take the test in their native language.

The English language test (reading, writing, speaking) has not changed.

USCIS provides free study materials including flashcards, practice tests, and the complete list of 128 questions with answers.

How Long Does Naturalization Take?

The current median processing time for Form N-400 is approximately 5.5 to 6 months from filing to oath ceremony. This is the fastest it's been since 2016, thanks to USCIS prioritizing citizenship applications.

But processing times vary significantly by field office. Some offices complete cases in under 4 months; others take 10 months or longer. Your local USCIS office is assigned based on your ZIP code, and you can check current processing times on the USCIS website.

The 90-day early filing rule: You can submit your N-400 up to 90 days before you meet the continuous residence requirement (3 or 5 years). This lets you get in line early, potentially shaving weeks off your total wait.

Factors that can delay your case:

• Incomplete or inaccurate applications
• Missing documents
• Background check issues
• Extended travel that raises questions about residence
• Rescheduling your biometrics or interview

Common Reasons for N-400 Denial

Understanding why applications get denied can help you avoid problems:

Application errors: Mistakes on your form, missing signatures, or inconsistent information can lead to rejections or denials. Double-check everything before you submit. If your forms are returned because of errors, you'll need to reapply and pay the fee again.

Physical presence and travel issues: If you can't prove you've spent enough days in the U.S. or if you've taken trips longer than 6 months without proper documentation, USCIS may deny your application or continue it until you meet the requirements.

Good moral character problems: Certain criminal convictions, tax issues, lying on previous immigration forms, or failing to support dependents can lead to denial. If you have any concerns in this area, consult an immigration attorney before filing.

Failing the tests: If you fail the English or civics test twice, USCIS will deny your application. You can reapply, but you'll need to pay the filing fee again.

Quick tip: For straightforward cases with no criminal history or complex travel patterns, most people don't need an expensive attorney. Guided preparation services can help you avoid common mistakes at a fraction of the cost.

Quick Takeaways

• Naturalization is the process of becoming a U.S. citizen after holding a green card for 3 to 5 years
• Form N-400 costs $710 online or $760 by mail; reduced fees and waivers are available for eligible applicants
• As of October 28, 2025, USCIS no longer accepts checks for paper filings
• The 2025 civics test asks 20 questions from a pool of 128; you need 12 correct answers to pass
• Applications filed before October 20, 2025 use the older 100-question test format
• Current median processing time is approximately 5.5 to 6 months
• You can file up to 90 days before meeting the residency requirement
• Common denial reasons include application errors, travel issues, and failing the tests twice

Becoming a U.S. citizen is one of the biggest steps you'll take. The form might be 20 pages long, but the process itself is straightforward if you prepare carefully.

Count your days. Know your dates. Make sure every answer on your application is accurate and consistent. Small errors can cause big delays, and filing fees aren't refundable.

For most people with straightforward cases (no complex travel history, no criminal issues), you don't need to spend thousands on attorney fees just to fill out forms. Immiva helps you prepare your N-400 with step-by-step guidance and real-time error checking, for just $49. Our platform catches mistakes before you submit, so you can file with confidence.

References

• USCIS Form N-400 Official Page
• USCIS 10 Steps to Naturalization
• USCIS 2025 Civics Test Information
• USCIS Fee Schedule
• USCIS Processing Times
• Federal Register: Notice of Implementation of 2025 Naturalization Civics Test