What’s a W-9 tax form and what should you do if you get one?

This article was fact-checked by our editors and Rachel Weatherly, tax product specialist with Credit Karma.

The IRS wants to know about all your income, and it doesn’t just take your word for it when you report your total income on your federal income tax return.

Generally, the organizations that provide your income — such as an employer, a company that contracts freelance work from you, or an IRA administrator — have to share that information with the IRS too. In order to do that, these organizations need some basic tax information from you, including your taxpayer identification number, name or business name, and address.

To obtain that information, a company may ask you to complete a W-9 tax form. The form also helps the company understand whether or not it should withhold tax from amounts it pays you.

Let’s look at the information on a Form W-9, when you might receive a request to complete one and what you should do if that happens.

• What is a W-9 tax form?
• What information is on a W-9?
• Who might ask me for a W-9?
• Will I have to fill out more than one W-9?
• What should I do with a completed Form W-9?

What is a W-9 tax form?

A W-9, Request for Taxpayer Identification Number and Certification, is a tax form that companies use to request a tax identification number, or TIN, from a taxpayer with whom they’re doing business.

Every person or company has a unique TIN that the IRS uses to identify that taxpayer. For individuals, that’s usually a Social Security number, which is issued by the Social Security Administration. People who must pay federal income tax, but aren’t eligible to get a Social Security number, can apply for an individual taxpayer identification number, or ITIN, from the IRS. For companies, the TIN is an employer identification number, which the IRS issues.

Your unique TIN must be submitted with all of your tax forms so that the IRS can easily identify your tax information.

When you’re a salaried employee, your employer can get your Social Security number from your W-4 — a tax form that tells it how much tax to withhold from your paycheck. But if you’re self-employed or earned income other than employee wages, the company or person who paid you may ask you to complete a W-9. Information on the form can help ensure the company uses your correct TIN when reporting any amounts it paid you during the tax year to the IRS.

The company will likely report those amounts to the IRS on some type of 1099 form. For example, a company might complete and file a Form 1099-MISC for a freelancer whom it paid $600 or more for services during the tax year.

What information is on a W-9?

A W-9 tax form contains some basic tax information, including …

• Your name as you write it on your income tax return
• Your business name, if it’s different from your name
• How you or your business are classified for federal tax purposes (sole proprietorship/individual or single-member LLC, limited liability company, corporation, partnership, or trust or estate)
• Your full address
• Your taxpayer identification number, with separate fields for a Social Security number (for individuals) or an employer identification number, or EIN, for businesses.

You’ll need to sign your W-9 form. By doing so, you certify that you’ve provided your correct taxpayer ID, that you’re a U.S. citizen or U.S resident alien, and that you aren’t subject to backup withholding tax or reporting requirements under the Foreign Account Tax Compliance Act, or FATCA.

Optional information can also be included on the form, including the name of the person or company requesting its completion. 

What is backup withholding?

In some situations, companies making certain types of payments may be required to withhold 24% of the payment amounts and pay it to the IRS. This is known as “backup withholding,” and it can kick in when a taxpayer …

• Fails to provide the company making a payment with their TIN.
• Provides the paying company with an incorrect TIN that doesn’t match the number the IRS has on file for that taxpayer.
• Doesn’t report on their tax return all the interest and dividends they were required to report.
• Doesn’t certify to the paying company that they’re not subject to backup withholding.

But if you do everything you’re supposed to do — give the company your correct TIN, include all your taxable interest and dividends on your tax return, and certify your exemption from backup withholding — you won’t be subject to backup withholding.

Who might ask me for a W-9?

Generally, if a company is required to file an information return with the IRS to report amounts of $600 or more paid to you during a tax year, it may ask you to complete a W-9 tax form. That means freelancers and independent contractors may receive a request for a W-9 from companies they do work for, but they’re not the only taxpayers who might receive a request to complete the form.

The IRS also requires companies to submit information returns for real estate transactions, mortgage interest a taxpayer pays to a mortgage company, canceled debts, IRA contributions and other situations. In those situations, companies may also ask a taxpayer for a W-9.

Will I have to fill out more than one W-9?

You might receive a request for more than one W-9.

For example, if you work with more than one company that pays you $600 or more, each one could ask you to complete a W-9 because they’ll all need your TIN to complete and file a 1099 for you. Companies may also complete 1099 forms even if you haven’t met the $600 threshold, just to make sure they’re properly reporting money they paid out when doing business.

You have to complete W-9 tax forms for every company that has a legitimate reason to request one, and you must complete the form accurately or face a penalty and possibly backup withholding in the future.

After you’ve filled out a W-9 once, you shouldn’t need to complete it again for the same requester. But if your information changes, you’re required to alert the company that asked for the W-9 that you need to modify your personal information. This is important so the requester has the right address and TIN to include on your 1099.

Be aware of identity theft

When you receive a request for a W-9, it’s probably a good idea to vet the requester to ensure they really do need the information they’re asking for. A W-9 contains sensitive information that could be valuable to identity thieves.

What should I do with a completed Form W-9?

When you complete a W-9, you’ll need to return it to the company, organization or individual who requested it from you. The IRS permits requesters to use an electronic system for receiving W-9s, but be sure you understand how the company requesting the form wants you to send it back.

It’s also a good idea to retain a copy of any tax form you complete throughout the year. There’s probably no one right answer for how long you should keep a copy of a W-9. But the IRS generally advises taxpayers to hold onto records for as long as they might need them to help document income or deductions on a tax return.

Bottom line

You should expect to receive a W-9 tax form from any company or individual, other than an employer, who paid you more than $600 per year. It’s a simple form, but make sure you fill it out accurately and provide your correct taxpayer identification number and address. The requesting company may need the information to prepare and file a 1099 that will let the IRS know how much it paid you during the tax year. And failing to properly complete a W-9 could mean your payments become subject to backup withholding.

Rachel Weatherly is a tax product specialist with Credit Karma. She studied accounting and finance at Western Carolina University and has also worked as a tax analyst. You can find her on LinkedIn.