How To Fill Out A W-9 Form: A Step-By-Step Guide

Whether you're hiring your first contractor or you've just been handed a W-9 to fill out yourself, the form can feel more confusing than it needs to be. IRS Form W-9—officially called the Request for Taxpayer Identification Number and Certification—is one of the most common tax forms in small business. But between tax classifications, TINs, and backup withholding, it's easy to second-guess every line.

The good news? The form itself is just one page (though the IRS includes additional instruction pages). And once you understand what each section is asking for, you can fill out a W-9 form in just a few minutes. This guide walks you through it line by line with plain-language explanations, tips for sole proprietors and LLCs, and the most common mistakes to avoid.

How to fill out a W-9 form quickly

Here's the short version. To fill out a W-9 form:

• Enter your legal name (Line 1)
• Add your business name if it's different (Line 2)
• Select your federal tax classification (Line 3)
• Enter your address (Lines 5–6)
• Provide your SSN or EIN (Part I)
• Sign and date the form (Part II)
• Submit it to the requester, not the IRS

That's it. If you need more detail on any of these steps, keep reading for a full breakdown.

What is a W-9 form?

A W-9 form is an IRS tax form that businesses use to collect a person's or entity's taxpayer identification number (TIN). Its official name is "Request for Taxpayer Identification Number and Certification."

If you're a contractor, freelancer, or vendor, a business will ask you to fill out a W-9 so they can accurately report the payments they made to you. They use the information on your W-9 to prepare Form 1099-NEC at the end of the year.

Here's what's important to know: a W-9 is not filed with the IRS in normal circumstances. The business that requested it keeps it on file for their own records unless the IRS specifically requests it during an audit or review. The current version was revised in March 2024, and that's the version you should use for 2025.

What is the point of filling out a W-9?

The W-9 serves one core purpose: it gives the requesting business your correct taxpayer identification number so they can report payments to the IRS.

Without a completed W-9, the business paying you may be required to withhold 24% of your payment and send it to the IRS. That's called backup withholding and it's triggered when a TIN is missing, incorrect, or hasn't been certified. A properly completed W-9 prevents that from happening.

It also helps both parties stay compliant. The business needs your W-9 to prepare accurate 1099 forms, and you need those 1099s to file your own taxes correctly.

Who is required to fill out a W-9?

If you're a U.S. person or entity receiving payments that aren't subject to regular tax withholding, you'll likely need to fill one out. That includes:

• Independent contractors and freelancers who provide services to a business
• Sole proprietors operating under their own name or a business name
• LLCs, single-member and multi-member
• Partnerships
• Some corporations (in limited situations, corporations are generally exempt from 1099 reporting, except for payments like medical and health care services or attorney fees)
• Vendors and landlords receiving reportable payments

One important distinction: employees fill out a W-4, not a W-9. The W-4 handles tax withholding for wages. The W-9 is specifically for non-employee payments. If you're not sure whether someone is an employee or a contractor, that classification matters — and getting it wrong can lead to penalties.

When do you need to request a W-9?

If you're a business owner or manager, you should collect a W-9 from any contractor or vendor before you make a payment, especially if you expect to pay them $600 or more during the tax year. That $600 threshold is when the IRS requires you to file a 1099-NEC reporting those payments. (Note: for payments made after December 31, 2025, the reporting threshold increases to $2,000.)

The best time to request a W-9 is during onboarding, before any work begins. Chasing down tax forms in January when 1099s are due is stressful and completely avoidable. If you're bringing on contractors regularly, building form collection into your onboarding process—rather than handling it over email or on paper—can save you a lot of headaches when tax season arrives.

How to fill out a W-9 form step by step

Now let's go through the form section by section. Each step covers exactly what to enter and why it matters. You can follow along with the official Form W-9 (Rev. March 2024).

Line 1: Legal name

Enter your name exactly as it appears on your federal tax return. If you're an individual or sole proprietor, this is your personal legal name, not your business name or DBA. If you're filling this out for a business entity like an LLC or corporation, enter the entity's legal name as registered with the IRS.

This line must match the name associated with your taxpayer identification number. A mismatch between your name and TIN is one of the most common reasons the IRS flags a return.

Line 2: Business name (if different)

If you operate under a business name, trade name, or DBA (doing business as) that's different from what you entered on Line 1, add it here. For example, if your legal name is Maria Santos but your catering business operates as "Santos Kitchen," you'd put Maria Santos on Line 1 and Santos Kitchen on Line 2.

If your business name and legal name are the same, leave this line blank.

Line 3: Federal tax classification

This is the line that trips people up most often. You need to check the box that matches your federal tax classification. Here's a quick breakdown:

This is the line that trips people up most often. You need to check the box that matches your federal tax classification. Here's a quick breakdown:

If you're an individual or sole proprietor, check "Individual/sole proprietor or single-member LLC." The same goes for a single-member LLC that hasn't elected corporate status.

If you're an LLC taxed as a corporation or partnership, check the "LLC" box and enter the appropriate letter in the classification field. So, "C" for C corporation, "S" for S corporation, or "P" for partnership.

C corporations, S corporations, partnerships, and trusts/estates each have their own dedicated checkbox.

If you're unsure about your entity's tax classification, check with your accountant or refer to your IRS determination letter. Choosing the wrong classification can create reporting issues down the road.

Line 4: Exemptions

Most individuals and sole proprietors can leave this line blank. Exemption codes apply to specific entities like banks, tax-exempt organizations, and certain corporations. If you're not sure whether an exemption applies to you, it probably doesn't, but corporations and exempt entities may need to enter a code. Check the IRS instructions for Form W-9 if you think an exemption might apply.

Lines 5 & 6: Address

Enter your mailing address: street number, street name, apartment or suite number, city, state, and ZIP code. This is the address where the requester will send your 1099 or other tax correspondence. Use the address associated with your tax filings to keep everything consistent.

Part I: Taxpayer Identification Number (TIN)

Your TIN is either your Social Security Number (SSN) or your Employer Identification Number (EIN). Which one you enter depends on your entity type:

• Individuals and sole proprietors: You may enter either your SSN or your EIN. Whichever you use, make sure it matches the name on Line 1. A mismatch is one of the most common triggers for IRS notices.
• Single-member LLCs (disregarded entities): Enter the owner's SSN or EIN, whichever is associated with the owner's tax return. The key is consistency. Your TIN and name must match IRS records.
• Multi-member LLCs, partnerships, and corporations: Use the entity's EIN.

Because a W-9 contains sensitive tax information like your SSN, it's important to store completed forms securely. Leaving them in shared email inboxes or paper filing cabinets creates unnecessary risk.

Part II: Certification

Sign and date the form. By signing, you're certifying under penalty of perjury that the TIN you provided is correct, that you're not subject to backup withholding (unless the IRS has told you otherwise), and that you're a U.S. person.

That sounds serious (and it is). But as long as the information you provided is accurate, signing is straightforward.

How to fill out a W-9 as a sole proprietor

Sole proprietors are the most common W-9 filers, and the form is fairly simple for this group:

• Line 1: Enter your personal legal name (not your business name).
• Line 2: Enter your DBA or business name if applicable.
• Line 3: Check "Individual/sole proprietor or single-member LLC."
• Part I: Enter either your SSN or your EIN, whichever matches the name on Line 1. Both are accepted by the IRS for sole proprietors.
• Line 4: Leave blank unless a specific exemption applies (it usually doesn't).

The biggest mistake sole proprietors make is entering their EIN instead of their SSN, which can cause the IRS to flag the form.

How to fill out a W-9 for an LLC

LLCs require a little more attention because your W-9 answers depend on how your LLC is classified for tax purposes.

• Single-member LLCs are treated as "disregarded entities" by the IRS. That means you check "Individual/sole proprietor or single-member LLC" on Line 3 and enter the owner's SSN in Part I, just like a sole proprietor.
• Multi-member LLCs are typically taxed as partnerships. Check the "LLC" box on Line 3 and enter "P" in the classification field. Use the LLC's EIN in Part I.
• LLCs that have elected corporate tax status should check the "LLC" box and enter "C" for C corporation or "S" for S corporation, depending on their election. Use the entity's EIN.

If you're unsure about your LLC's tax classification, your formation documents or a letter from the IRS (like CP 575) should confirm it. Getting this wrong can create mismatches between your W-9 and the 1099 the business files, which can trigger IRS notices.

What happens after you submit a W-9?

Once you hand over your completed W-9, a few things happen:

• The requester keeps it on file. The W-9 is not sent to the IRS. The business that requested it stores it and uses the information to prepare tax forms at year-end. The IRS recommends keeping W-9s on file for at least four years.
• They use it to prepare your 1099. If the business pays you $600 or more during the tax year (or $2,000 or more for payments made after December 31, 2025), they're required to file a 1099-NEC with the IRS and send you a copy. The filing deadline is January 31 of the following year.
• You should keep your own records too. While you don't file the W-9 yourself, it's a good idea to keep a copy so you have a record of what you submitted. If your information changes—say you form an LLC or get a new EIN—you'll need to submit an updated W-9.

For business owners, staying organized with contractor records throughout the year makes 1099 filing season much less painful. When all your W-9s, payment records, and contractor details live in one place instead of scattered across spreadsheets and email threads, the January deadline doesn't have to feel like a scramble.

What are common W-9 mistakes to avoid?

Even though the form is just one page, errors happen more often than you'd think. Here are the most common ones:

• Choosing the wrong tax classification. This is the number one mistake, especially for LLCs that don't know their federal tax classification.
• Name-and-TIN mismatch. Your TIN must correspond to the name on Line 1. If they don't match, the IRS may flag the return or trigger backup withholding.
• Forgetting to sign the form. An unsigned W-9 isn't valid. The requester can't use it until Part II is signed and dated.
• Confusing a W-9 with a W-4. A W-9 is for contractors. A W-4 is for employees. Sending the wrong form creates compliance issues for everyone.
• Sending the W-9 to the IRS. The W-9 goes to the business that requested it, not to the IRS. Filing it directly with the IRS is unnecessary and won't accomplish anything.
• Leaving Line 1 blank. Your legal name is required. Skipping it means the form can't be processed.

If you're the one collecting W-9s, a quick review before filing can catch these issues early and save you from correcting 1099s later.

W-9 vs. W-4: what's the difference?

These two forms serve very different purposes, and mixing them up can cause real problems.

A W-9 is filled out by contractors, freelancers, and vendors. It provides the business with a TIN so they can prepare a 1099-NEC at year-end. The contractor is responsible for paying their own taxes.

A W-4 is filled out by employees. It tells the employer how much federal tax to withhold from each paycheck. It leads to a W-2 at year-end, and the employer handles withholding.

Neither form gets filed with the IRS. Employers generally keep both on file and don't submit them unless specifically requested.

The simplest way to remember it: W-9 = contractor. W-4 = employee. If you're managing both employees and contractors, keeping these forms organized and classified correctly is essential. Misclassifying a worker can result in back taxes, penalties, and interest from the IRS.

How to fill out a W-9 FAQs

How do I fill out a W-9 form?

Enter your legal name on Line 1, add a business name on Line 2 if it's different, select your tax classification on Line 3, provide your address on Lines 5–6, enter your SSN or EIN in Part I, and sign Part II. Submit the completed form to the business that requested it, not to the IRS.

What are common W-9 mistakes to avoid?

The most frequent mistakes include selecting the wrong tax classification, using an EIN instead of an SSN as a sole proprietor, forgetting to sign the form, and confusing the W-9 (for contractors) with the W-4 (for employees). Always double-check your TIN matches the name on Line 1.

What is the point of filling out a W-9?

A W-9 provides your taxpayer identification number to a business so they can accurately report payments they made to you. Without it, the business may have to apply backup withholding at 24% of your payments. It also ensures your 1099 is accurate at tax time.

Who is required to fill out a W-9?

Any U.S. person or entity receiving non-employee payments may need to complete one. This includes independent contractors, freelancers, sole proprietors, LLCs, partnerships, and some vendors. Employees fill out a W-4 instead.

Paying contractors doesn't have to be complicated

If you're a small business owner, W-9s are just one piece of the contractor puzzle. You also need to track payments, stay on top of 1099 deadlines, and make sure your records are organized enough to survive tax season without losing your mind.

That's a lot to manage, especially when you're also running a business, managing a team, and handling day-to-day operations.

Homebase gives you one place to manage contractor and employee records, collect tax forms, track payments, and run payroll without juggling spreadsheets and email threads. Whether you're paying your first contractor or your fiftieth, everything stays organized in one app. Try Homebase payroll.

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