How to fill out Form W-9 (Rev. March 2024): line by line

Tax forms › Form W-9 · Last reviewed October 25, 2026 · General information, not tax advice

Form W-9 at a glance

What it does	Gives you a payee's legal name, tax classification and TIN for 1099 reporting
Who completes it	The contractor, landlord or other payee; you keep it
When	Before the first payment
Filed with the IRS?	No
Current revision	Rev. March 2024

What Form W-9 is

Form W-9 is how a US person gives you their correct taxpayer identification number (TIN) and certifies they are not subject to backup withholding. You use it to prepare Forms 1099-NEC and 1099-MISC, and to know whether a payee is a corporation that does not need one.

The current revision is dated March 2024. It added line 3b, where flow-through entities such as partnerships and trusts tick a box if they have foreign partners, owners or beneficiaries.

Who has to file

Ask every contractor, freelancer, landlord, attorney and other payee you may need to report on a 1099, before you pay them.
Foreign persons do not complete a W-9; they give you a Form W-8 instead.
Employees do not complete a W-9; they give you a W-4.

Due dates

What	Due
Request it	Before the first payment; payment terms can say no payment until the W-9 is received
If you do not have a TIN	Start backup withholding at 24% on reportable payments
Keep it	At least 4 years after the last return it supports

Penalties for filing late or wrong

A payee who does not give you a correct TIN can be charged a $50 penalty by the IRS for each failure.
If you have no TIN, or the IRS tells you a TIN is wrong (a B notice), you must withhold 24% from reportable payments. If you should have withheld and did not, you owe the tax.
A payee who gives false information to avoid backup withholding can face a $500 civil penalty and criminal penalties.

Form W-9 line by line

Line	What the payee enters	What you check
1	Name as shown on their income tax return; for a single-member LLC, the owner's name	This is the name that goes on the 1099 and must match the TIN
2	Business name or disregarded entity name, if different	Use it as the second name line on the 1099
3a	Federal tax classification: individual/sole proprietor, C corporation, S corporation, partnership, trust/estate, or LLC with its tax classification (C, S or P), or other	Corporations (other than for attorney fees and medical payments) do not need a 1099; a single-member LLC owned by an individual is treated as a sole proprietor
3b	Tick if a partnership, trust or estate with foreign partners, owners or beneficiaries	Only relevant if you file Form 1065 or 1041-type reporting; otherwise note it
4	Exempt payee code and FATCA exemption code, if any	Most small businesses and individuals leave this blank
5, 6	Address (number, street, city, state, ZIP)	Where you mail the 1099
7	Account numbers (optional)	Your vendor number, if you want one on the form
Part I	TIN: Social Security number or employer identification number	Nine digits; for a sole proprietor either their SSN or the business EIN, matching line 1
Part II	Signature and date certifying the TIN, backup withholding status, US person status and FATCA codes	An unsigned form is not a valid certification for backup withholding purposes

Common mistakes

Line 1 with the business name and an SSN that belongs to the owner. The name and TIN must match each other.
A single-member LLC that puts the LLC name on line 1 with the LLC's EIN when it is a disregarded entity.
Accepting a W-9 by email with the SSN in plain text. Use a secure channel.
Never asking. You learn in January who crossed the threshold, and by then the contractor may be hard to reach.
Using a W-9 for a foreign contractor, who needs a W-8BEN or W-8BEN-E.

How to file Form W-9

Send the current form. Give the payee the March 2024 revision of Form W-9 before the first payment.
Check what comes back. Make sure line 1, the tax classification and the TIN agree, and that the form is signed.
Record it. Enter the legal name, address, TIN and whether the payee needs a 1099 on the vendor record.
Verify the TIN. If you are registered, check the name and TIN with the IRS TIN Matching program.
Keep it secure. Store the W-9 for at least four years, with access limited to the people who need it.

How AcboBooks fills it in

AcboBooks 0.2.1 does not generate a W-9, but it holds what you collect from one. Each vendor can be flagged for 1099 tracking and has a tax ID and mailing address that the 1099-NEC wizard uses. The wizard outlines a missing TIN in red, so you see who still owes you a W-9 before you print.

Described as of AcboBooks 0.2.1. See 1099 tracking in AcboBooks

Questions

What is the latest version of Form W-9?

The revision dated March 2024. It added line 3b for flow-through entities with foreign partners, owners or beneficiaries. The IRS lists no newer changes as of October 2026.

Do I send the W-9 to the IRS?

No. You keep it and use it to prepare 1099s. The payee does not send it to the IRS either.

What happens if a contractor will not give me a W-9?

You must start backup withholding at 24% on reportable payments to them and send that tax to the IRS. You still file the 1099, showing the withholding in box 4.

Do corporations need to fill out a W-9?

You can still ask for one: it tells you they are a corporation, which means most payments to them need no 1099. Payments to attorneys and for medical and health care services are reported even when the payee is a corporation.

Sources

Checked against these sources on October 25, 2026. Dates assume a calendar year and apply the next-business-day rule for weekends and holidays.

General information, not tax or legal advice. Forms, thresholds and dates change; confirm with the IRS and SSA or a tax professional before you file.