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What Is USCIS Form N-400?

In a Nutshell

Form N-400 is officially called the Application for Naturalization. You need to submit Form N-400 to U.S. Citizenship and Immigration Services (USCIS) to apply for U.S. citizenship. This article will explain if you qualify to file Form N-400, how to file, how much it costs, and how long USCIS will normally take to process your Form N-400.

Written by Jonathan Petts
Updated November 22, 2022

Who Can File Form N-400?

You’re only eligible to file Form N-400 if you qualify to become an American citizen by naturalization. To qualify for naturalization, you must have held a green card for at least five years, or at least three years if you are married to a U.S. citizen. In addition, you’ll have to be at least 18 years old. If you’re applying for citizenship based on military service, the requirements will be a little different for you.

Who Can’t File Form N-400?

You shouldn’t use Form N-400 if you’re a child of a U.S. citizen and live abroad. Instead, you’ll file Form N-600 to get a certificate of citizenship (also called a certificate of naturalization). People with “derived” or “acquired” citizenship also can’t file the N-400; they have a separate citizenship application.

How Much Does It Cost To File Form N-400?

Like many immigration forms, Form N-400 has a government filing fee. It currently costs $725 to submit Form N-400. Of the $725 total, $640 goes to processing your form and $85 covers biometrics services. Applicants who are over 75 years old don’t have to pay the biometrics fee; their total will be $640. U.S. Citizenship and Immigration Services (USCIS) will not refund your filing fee whether they approve or deny your application. 

You can pay your filing fee with a personal check, cashier’s check, or money order payable to the U.S. Department of Homeland Security. If you address your check to any other name, even an abbreviation like DHS or USDHS, USCIS will not process your payment. You can also pay the fee with a credit card by completing and signing Form G-1450.

If you cannot afford the filing fees, you may be eligible for a fee waiver or fee reduction. Check out our article on how to get a fee waiver to learn more.

What Supporting Documents Must You Provide With Form N-400?

Everyone who’s applying for naturalization must include supporting documents with their Form N-400 before filing it with U.S. Citizenship and Immigration Services (USCIS). You always must submit a photocopy of the front and back of your green card (also known as Form I-551 or the permanent resident card).

In addition, depending on your specific circumstances, like where you’re applying from and your green card type, you may also have to include one or more of these supporting documents:

  • Two identical color passport photos that are 2-by-2 inches in size

  • Proof of your marital status, including a marriage, divorce, or death certificate if applicable

  • Certified English translations of any required documents that are in a foreign language

  • Tax documents

  • Form N-648, Medical Certification for Disability Exceptions 

You can find the full list of required documents and additional information for your specific circumstances on the USCIS website. You should only send copies of your original documents to USCIS.

How Do You File Form N-400?

You can submit Form N-400 either online through the U.S. Citizenship and Immigration Services (USCIS) website or by postal mail to a USCIS service center or lockbox. If you’re filing from abroad or applying for a fee waiver though, you must use the paper form and send it by mail.

To submit the paper form, you have to download and print the form from USCIS’s website and complete it using black ink. The address you will mail your application package to will depend on the state you live in and the delivery service you use. You can find the correct mailing address on the USCIS website. To file Form N-400 online, you have to create a USCIS online account on the USCIS website. With your online account, you can pay the fee online and upload copies of your supporting documents.

After you file, USCIS will invite you for a naturalization interview at a USCIS field office. At the USCIS office, you will answer questions about your application and take English language and civics tests. If you pass the tests, the last step in the process will be to take the oath of allegiance at an oath ceremony where you’ll officially become a U.S. citizen.

How Early Can You File Form N-400?

To determine how early you can file Form N-400, you’ll first need to know if you meet the five-year rule or three-year rule. These rules refer to the amount of time you’ve been a U.S. lawful permanent resident. 

Under the five-year rule, if you have held your green card for at least five years, you’re welcome to apply for naturalization as a U.S. citizen. But some green card applicants can file Form N-400 even earlier under the three-year rule. Specifically, spouses of U.S. citizens can apply for citizenship after having their green card for only three years if they have been married to their American partner for at least three years. 

Certain other applicant groups like widows of people who died while serving in the U.S. Armed Forces can apply for naturalization at any time. They don’t have a required number of years as a  permanent resident to be eligible to apply. Check the USCIS website for information on whether you qualify for an exemption from the five-year or three-year eligibility requirements.

Early Filing

The earliest you can file a Form N-400 application is 90 days before your third or fifth anniversary as a lawful permanent resident. This is called early filing. Although U.S. Citizenship and Immigration Services (USCIS) will not approve your naturalization application until you meet the full three-year or five-year requirement, they will accept your application as early as 90 calendar days before then. Remember that any time spent outside of the United States since you received your green card does not count toward the requirement.

You can use the USCIS calculator to check the earliest day you can file. You’ll have to enter the date that is three or five years (as applicable) from the date on your green card — your “anniversary date.” The calculator will subtract 90 days and tell you when is the earliest you can submit your application.

How Long Does It Take To Process Form N-400?

It takes an average of 12 months for U.S. Citizenship and Immigration Services (USCIS) to complete your Form N-400’s processing. USCIS keeps a record of application processing times on its website that you can refer to. With increased backlogs and other complications from the coronavirus pandemic, you may end up waiting longer for USCIS to process your application. You can track how far along your naturalization process is at any time by entering your receipt number on the USCIS case status tracker.

Can You Expedite Form N-400?

USCIS’s premium processing service does not apply to Form N-400. But you may be able to expedite your Form N-400’s processing if you get in touch with the USCIS Contact Center. To request expedited processing, you’ll need to have your receipt number and A-number on hand, as well as your personal copy of your application so you can provide any case details quickly and accurately.


Filing Form N-400 can be complicated, but help is available. If you are eligible, our free web app will walk you through the naturalization process and help you prepare and file your application with the U.S. government. If our app isn’t a good fit, we may be able to refer you to an experienced immigration attorney to help. Click "Get Started" to see how we can help make your American dream come true!

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