Your Guide To Form N-400 and the Citizenship Application

In a Nutshell

Form N-400 is officially called the Application for Naturalization. This is the form you use to apply for U.S. citizenship with U.S. Citizenship and Immigration Services (USCIS). You can apply for citizenship through naturalization if you are at least 18 years old and you are a green card holder in good moral standing. Naturalization applications currently take, on average, 18 months to process through USCIS. N-400 forms cost a total of $725 to file.

Written by ImmigrationHelp Team
Updated March 21, 2023


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

The current average USCIS processing time for Form N-400 is 15.5 months. This is just one step in the naturalization process, which takes 18–24 months on average and includes application processing, your citizenship exam and interview, and the oath of allegiance ceremony. 

Your N-400 process time will depend, in part, on which USCIS field office is reviewing your case. Each week, we review and publish USCIS Form N-400 processing times so you can find the most up-to-date information on our site.

Can I Expedite My Form N-400? 

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 ready, as well as a copy of your application so you can provide any case details quickly and accurately.

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. With a few exceptions, applicants for U.S. citizenship need to meet the following eligibility requirements: 

  • Must be at least 18 years old

  • Must be a green card holder for at least five years OR at least three years if married to a U.S. citizen

  • Must have lived in the same U.S. state for at least three months before applying

  • Must know the fundamentals of U.S. history and the U.S. government

  • Must be able to speak, read, and write English 

  • Must be able to demonstrate that you are of good moral character

If you’re applying for citizenship based on military service, the requirements will be a little different for you.

You can learn more about applying for U.S. citizenship in our Citizenship Guide.

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 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 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.

What You Need To Know About Filing Form N-400 by Mail

To submit the paper form, you have to download and print the form from USCIS’ website. 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

Keep these tips in mind when filing by mail:

  • Use black ink.

  • Make sure you’re filling out the most current forms.

  • Do not file a form by mail if you have already filed it online.

  • Don’t forget to sign your forms. USCIS will reject your citizenship application if you don’t sign your forms.

What You Need To Know About Filing Form N-400 Online

To file Form N-400 online, you have to create a USCIS online account. Once you have an online account, you can pay the filing fee online and upload copies of your supporting documents directly to the USCIS website.

After you file, USCIS will schedule a naturalization interview at a USCIS field office near you. At the interview, 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 is taking the oath of allegiance at an oath ceremony where you’ll officially become a U.S. citizen.

Need help preparing for the citizenship test? Check out our Citizenship Test Guide.

What Supporting Documents Do I Have To Send With Form N-400?

Everyone who is applying for naturalization must include supporting documents with their Form N-400 application. 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).

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 

If you’re mailing your packet, make copies of your original documents and send those copies to USCIS unless an officer specifically requests an original form. You can find the full list of required documents and additional information on the USCIS website.

When Can I 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 lawful permanent resident in the U.S. 

  • The Five-Year Rule: If you have had a green card for at least five years, you’re welcome to apply for naturalization as a U.S. citizen. 

  • The Three-Year Rule: 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. 

Other Applicants Filing Form N-400

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 to wait a required number of years as a permanent resident to be eligible to apply. 

Early Filing: The 90-Day Form N-400 Application Rule

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. U.S. Citizenship and Immigration Services (USCIS) will not approve your naturalization application until you meet the full three-year or five-year requirement, but it will accept your application to begin the process. You’re simply getting a head start on filing your application. 

You can use the USCIS calculator to check the earliest day you can file. You’ll have to enter your “anniversary date”— the date that is three or five years (as applicable) from the date on your green card. The calculator will subtract 90 days and tell you the earliest day you can submit your N-400 application.

Remember that any time spent outside of the United States since you received your green card does not count toward the requirement.

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

It currently costs $725 to submit Form N-400: $640 for processing your form and $85 for biometrics services. Applicants who are over 75 years old don’t have to pay the biometrics fee — their total will be $640.

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