W-9 form and backup withholding for contractors
Why to collect a Form W-9 before the first payment, what it contains, and what backup withholding means if a contractor does not provide a valid taxpayer ID.
Form W-9 (Request for Taxpayer Identification Number and Certification) is how a US contractor gives you the details you need to report payments to the IRS. It contains the contractor's name, address, tax classification, and taxpayer identification number (TIN). You do not send it to the IRS; you keep it. If a payee does not provide a correct TIN, the IRS can require the payer to withhold backup withholding, currently 24 percent of certain reportable payments, and pay it to the IRS. Whether backup withholding applies to a specific payment depends on the type of payment and the IRS rules, so read the current IRS instructions. Asking for the W-9 before the first invoice is paid avoids surprises at year end. 4invoices does not collect, store, or verify W-9 data.
- Ask for a W-9 from each US contractor before the first payment.
- The W-9 shows name, address, tax classification, and TIN; you keep it, you do not file it.
- Backup withholding is 24 percent, and applies when a payee's TIN is missing or incorrect.
- Check the current IRS instructions for which payments are covered.
How it works
Send the current W-9 with your onboarding. Use the IRS's official form from irs.gov and ask for it before you approve the first invoice.
Read the tax classification. The box the contractor checks tells you whether the payments are likely to be reported on Form 1099-NEC. Read the IRS instructions for exceptions.
Store it safely. It contains a taxpayer ID, so restrict access and do not email it unprotected.
Watch for TIN problems. If the IRS notifies you that a name and TIN do not match, follow the notice's instructions and deadlines.
Withhold if required. When backup withholding applies, deduct it from payments, deposit it as the IRS directs, and report it at year end. Ask your accountant for the deposit and reporting steps.
Legal references
- IRS Form W-9 and its instructions — the request for taxpayer identification number and certification.
- IRS Publication 1281, Backup Withholding for Missing and Incorrect Name/TIN(s) — when and how to withhold.
- IRS Instructions for Forms 1099-MISC and 1099-NEC — reporting rules for contractor payments.
Frequently asked questions
Do I send the W-9 to the IRS?
No. The payer keeps the W-9 and uses it to prepare information returns such as Form 1099-NEC. Only the contractor completes it.
What if a contractor refuses to give a W-9?
You may be required to apply backup withholding on reportable payments. Read the current IRS guidance and ask your accountant before you pay.
Does a foreign contractor complete a W-9?
No. Foreign persons generally use a Form W-8 series form instead. Check the IRS instructions for the right form.
Does 4invoices collect W-9s or apply backup withholding?
No. 4invoices creates invoices with a tax rate per line, any currency with an exchange rate, and PDF downloads. It does not collect or store W-9 forms, verify taxpayer IDs, withhold tax, or file with the IRS.