An employer identification number (EIN) identifies your business, while an individual taxpayer identification number (ITIN) identifies you as an individual. If you’re incorporating a startup in the US, you need an EIN in every case, but whether you also need an ITIN depends on your personal tax situation. Understanding the difference between an EIN and an ITIN is important for correctly setting up business accounts and filing taxes.

Below, we discuss what each ID actually does, how their use differs in practice, and how to determine which ID(s) apply to your situation.

Key takeaways

• An EIN identifies a business and is required for every incorporated business, regardless of the founders’ citizenship or residency status.

• An ITIN identifies an individual and only becomes relevant for founders who have a personal US tax filing requirement.

• The two obligations are triggered separately. A company can hold an EIN long before any of its foreign founders needs an ITIN.

What is an EIN?

An EIN is a nine-digit tax ID the Internal Revenue Service (IRS) assigns to a business. It’s formatted like this: XX-XXXXXXX. Your EIN identifies your company on tax filings, payroll records, and bank paperwork. If you’re incorporating a startup, you’ll need an EIN before you can open a business bank account.

You can get an EIN for free through the IRS. If you already have a Social Security number (SSN) or an ITIN, you can apply for an EIN online through the IRS EIN Assistant and get your number in the same session. If you don’t have an SSN or ITIN, you can apply for an EIN by calling the IRS’s international line; you might need to fax or mail Form SS-4 to the IRS as well. Applications by fax typically take about four business days to process and those by mail typically take about four weeks.

What is an ITIN?

An ITIN is one form of taxpayer identification number (TIN). It’s a personal tax ID for people who need to file US taxes but don’t qualify for an SSN. It’s formatted like an SSN but always starts with a 9 (e.g., 9XX-XX-XXXX), which is how the IRS and banks tell it apart from an SSN at a glance. Founders who aren’t US citizens or permanent residents might need an ITIN if they earn US-source income and need to file a personal return, such as Form 1040-NR. Some nonresident founders also use an ITIN to open a personal bank account, though policies vary by bank.

To apply for an ITIN, submit Form W-7 to the IRS. Every ITIN application requires mailing an original document (or certified copy) or making an in-person appointment with an IRS-approved certifying acceptance agent. There’s no online option, and processing typically takes about seven weeks—longer during filing season or when submitting from outside the US.

ITINs expire. If you don’t use your ITIN on a federal return for three consecutive tax years, the IRS deactivates it; if you need it again later, you’ll need to apply for renewal by going through the original application steps.

What’s the difference between an EIN and an ITIN?

An EIN identifies a business entity, while an ITIN identifies a person. More specifically, EINs are issued to businesses, trusts, and estates, while ITINs are issued to individuals who need to file US taxes but who can’t get an SSN, such as nonresident founders, foreign investors receiving US income, or dependents of US taxpayers living abroad.

These numbers serve different purposes. An EIN lets a company open a business bank account, file corporate returns, run payroll, and register for state tax accounts. An ITIN lets a nonresident file a personal return, claim tax treaty benefits, and, in some cases, open a personal bank account or apply for certain credit products.

Do I need an EIN or an ITIN for my startup?

All incorporated businesses need an EIN from the moment they start. However, they need an ITIN only if the founder is a nonresident with US-source income to report. A nonresident who takes a salary or draws income connected to a US business, for example, will likely need to file Form 1040-NR, which requires an ITIN or SSN. In contrast, a nonresident who holds equity but takes no US income and has no US filing requirement can often skip the ITIN entirely.

How does a founder apply for an EIN?

A founder with an SSN or ITIN can go to the IRS EIN Assistant, complete the application, and receive an EIN upon submission. The tool is available to use Monday through Friday, 7 a.m. to 10 p.m. Eastern time. A user session times out after 15 minutes of inactivity, so it’s worth having everything you need ready before you start, including your entity details (legal business name, date and US state of incorporation, and the responsible party’s taxpayer ID number, or TIN).

If you’re applying for an EIN as a nonresident founder without an SSN or ITIN, you can’t use the online assistant. Instead, complete Form SS-4 and call the IRS’s international line at 267-941-1099 (not toll-free). An IRS representative will take your information over the phone and can issue the EIN during the call. If requested by the representative, you’ll need to sign and fax or mail the completed SS-4 within 24 hours to finalize it.

Founders who incorporate through Stripe Atlas skip much of this manual work. Atlas incorporates the company as a Delaware C corporation and handles the EIN application as part of that process, so the number typically gets issued within the incorporation timeline rather than requiring a separate call to the IRS.

Whichever path you take to getting your EIN, be sure to safely store your confirmation notice, whether it’s the CP575 the IRS mails or the confirmation letter Atlas provides. Banks and payroll providers will ask for this notice when you open accounts or run your first payroll cycle.

How Stripe Atlas can help

Stripe Atlas handles everything you need to legally launch your company—incorporation, employer identification number (EIN), equity setup, and tax filings—so you can fundraise, open a bank account, and start accepting payments in as little as two business days, from anywhere in the world.

Join 100,000+ startups incorporated using Atlas, including startups backed by top investors like Y Combinator, a16z, and General Catalyst.

Get started in minutes with Atlas

The application takes under 10 minutes. You’ll choose your company structure, confirm your name is available, add up to four cofounders, set your equity split, and e-sign. Then Atlas takes it from there, including notifying cofounders to sign their documents electronically.

Banking and payments before your EIN arrives

Atlas files your EIN application automatically after incorporation. You don’t have to wait—Atlas enables pre-EIN payments and banking so you can start accepting payments and making transactions right away. US founders with a Social Security number are typically eligible for expedited IRS processing.

Automatic 83(b) tax election filing

Atlas files your 83(b) election for you—US and non-US founders alike—with US Postal Service certified mail and tracking to reduce personal income taxes. You’ll get a signed 83(b) election and proof of filing directly in your Stripe Dashboard, with certified mail confirmation.

World-class company legal documents

Atlas provides all the legal documents you need to start running your company, drafted by Cooley, one of the world’s leading venture capital law firms, and stores them directly in your Stripe Dashboard. These documents are designed to help you fundraise immediately and ensure your company is legally protected, covering aspects like ownership structure, equity distribution, and tax compliance.

$2,500 in Stripe credits, plus $50K+ in partner discounts

Atlas startups get $2,500 in Stripe product credits for their first year, plus $50,000+ in discounts on essential tools—AWS, Google, Xero, Perplexity, and more. Delaware registered agent service is also included free for your first year.

Learn more about how Atlas can help you set up your new business quickly and easily, and get started today.

FAQs about EIN vs. ITIN