What Is a W-9? Definition and Who Fills It Out

Form W-9 is an IRS document that businesses use to collect a person's tax identification number (TIN). Independent contractors who were paid at least $600 during the year need to fill out a W-9.

Workers with W-9 status don’t usually have income taxes withheld from their payments. Instead, an independent contractor’s clients report payments to the IRS, and it’s up to the worker to settle up, usually through quarterly estimated tax payments.

A business or other entity may also request a completed Form W-9 in a few other situations. Examples include mortgage interest payments, IRA contributions, dividend income, real estate transactions, and proceeds from investment sales^[0]

Independent contractors, gig workers, freelancers and anyone else who is paid outside an employer/employee relationship might have to fill out a W-9 form.

In most cases, the IRS says a business should ask for a W-9 form if it is paying an independent contractor who meets the following criteria:

1. The worker is not an employee.

2. The payment is part of your business.

3. The annual value of the payments is at least $600.

At the end of the year, businesses are expected to tally up their payments to W-9 workers and report them to the IRS and the contractors, usually on Form 1099-NEC.

The main piece of information that businesses collect on a Form W-9 is the tax identification number of the person they’re paying. This can be a Social Security number or an employer identification number.

But that's not the only information you need to provide on a W-9. Here's a breakdown of how to fill out each section of the W-9.

If you're asked to fill out a W-9, be sure to put it on the top of your to-do list. Failure to provide an accurate tax ID may subject you to backup withholding: an automatic 24% tax on your earnings enforced by the IRS.

The IRS published an updated version of the W-9 form in March 2024^[0]

The revised W-9 adds a new line 3b for those who choose "partnership" or "trust/estate," asking them to indicate whether the partnership, trust or estate has foreign partners, beneficiaries or owners.

Businesses use W-9 forms to collect taxpayer identification numbers for nonemployees who work for them during the year. They can then use these TINs to help them fill out 1099 forms at the end of the year.

Remember that the IRS gets a copy of any 1099s, too, so be sure to accurately report any payments you received during the year when filling out your tax return.

» MORE: What is a 1099, and how does it work?

The main difference between Form W-9 and Form W-4 is that Form W-9 is for independent contractors and other people who are not employees, while Form W-4 is for more traditional employment relationships.