W-4, I-9, and W-9
Three different forms for three different moments: hiring an employee, proving work authorization, and paying a contractor.
General information, not tax or legal advice. Which form applies follows from whether the person is an employee. This page does not make that decision. The factors are on 1099-NEC versus W-2.
Do not collect one packet for every human
Form W-4 tells an employer how to withhold federal income tax from wages. Form I-9 is the employment eligibility form from U.S. Citizenship and Immigration Services, completed for each person hired for employment in the United States. Form W-9 asks a U.S. person for a taxpayer identification number so you can file an information return if one is required. An employee does not give you a W-9 instead of a W-4. A contractor does not complete an I-9.
What to do, and when
- Decide the relationship first. Employee or independent contractor. The IRS categories are behavioral control, financial control, and the relationship. The cost gap on the employee versus contractor cost page is not the decision.
- For an employee, collect Form W-4. The IRS form is how the employee tells you about withholding. Withholding is then a payroll liability, not an expense. Gross wages and employer taxes are the expenses. The paycheck estimator is a rough picture, not a substitute for the form or for Publication 15-T.
- Complete Form I-9 on the USCIS clock. USCIS states that employees complete Section 1 no later than the first day of employment, and that the employer completes Section 2 within three business days of the date of hire. If you hire someone for fewer than three business days, Section 2 is due no later than the first day of employment. The employer reviews the employee’s documents. This site does not list acceptable documents; the form instructions do.
- For a contractor, request Form W-9 before you pay. You need the name, address, and taxpayer identification number if you later have to file Form 1099-NEC. For payments made in 2026 the reporting threshold is $2,000. Keep the total even when it is under the threshold. The year-end checklist is when you add the payees up.
- File the forms in the books, not in wage expense. A W-4 and an I-9 are records, not journal entries. The journal entry is still the wage or the contract-labor payment.
Retention is not one number for all three
USCIS states that you must retain a Form I-9 for three years after the date of hire, or one year after employment ends, whichever is later. IRS retention for employment-tax records is a different instruction. Do not apply the I-9 period to a W-4, or the other way around. Read the current form instructions for each.
Sources
- IRS: About Form W-4 — employee’s withholding certificate.
- USCIS: Completing Form I-9 — Section 1 by the first day; Section 2 within three business days of hire.
- USCIS: Retaining Form I-9 — three years after hire or one year after employment ends, whichever is later.
- IRS: About Form W-9 — request for a taxpayer identification number.
- IRS: Information returns — $2,000 Form 1099-NEC threshold for payments made in 2026.