Ask before the first payment
The easiest moment to get a W-9 is when you onboard the vendor, before any money moves. After a payment, the contractor has less reason to respond. Put it in your new vendor checklist alongside the contract and the invoice instructions.
Use the current IRS version of the form, which is free on the IRS website. Do not use a version found in a random template library, as it may be outdated.
Review each form when it arrives
Check that the name matches the tax classification box, that the address is complete, that the form is signed and dated, and that a taxpayer identification number is entered. The name should be the one the IRS has on file for that number.
If a contractor operates through an LLC, the form should reflect the correct classification for that entity. Questions about which box to choose are for the contractor and their own tax advisor, not you.
Store it as sensitive information
A W-9 contains a Social Security or employer number. Do not leave it in an email inbox, a shared folder everyone can open, or a paper pile on a desk. Keep it in an encrypted folder or a secure document system with restricted access, and delete copies from email after filing.
Do not paste the number into notes fields of your accounting software that many people can see. Most programs have a dedicated tax ID field with limited visibility.
If a contractor will not provide one
Document your requests with dates. Federal rules may require backup withholding on payments when a taxpayer identification number is missing or incorrect. This is a real obligation with its own deposits and reporting, so check the current rules with the IRS or a CPA before paying.
A refusal to provide a W-9 is also a reason to reconsider the relationship.
Keep a vendor tracker
Make a simple sheet listing each vendor, whether a W-9 is on file, the date, whether the vendor is a corporation or an individual, and total paid during the year. In January it becomes your filing list.
Update the tracker whenever a vendor changes name, structure or address, and ask for a new form in that case.
Sample onboarding order for a new vendor
A tidy sequence looks like this. Agree on scope and price, send the W-9 and ask for it back signed, receive it and check it, enter the vendor into your accounting file with the tax ID field filled in, and only then approve the first invoice. Each step is short, and the order protects you.
For a one-off purchase from a business that is clearly a corporation selling goods, you may decide a form is unnecessary. Write down that decision in the vendor notes so the choice is visible later.
Common questions
Do I send the W-9 to the IRS?
No. You keep it in your records. It is the source of information used to file information returns.
Do I need a W-9 from every vendor?
Not every vendor will receive an information return, but it is practical to request one from every individual or unincorporated provider you may pay.
How long do I keep W-9 forms?
Keep them with your other tax records and ask your preparer about the period that applies.
This guide is general information, not tax, legal or accounting advice. Rules, fees and due dates change; check with the IRS, the NJ Division of Taxation or a licensed professional for your situation.