Can a Minor Fill Out a W9? Who Signs and Which TIN to Use

Yes, a minor can fill out IRS Form W-9. There is no minimum age, and any person who earns reportable income in the United States needs a completed W-9 on file with whoever is paying them, including a child doing freelance work, earning bank interest, or receiving prize money.¹ The form is short. The rules around who signs it, what tax ID goes on it, and what happens afterward are what deserve attention when a child’s information is involved.

Who Signs a W-9 for a Minor

The W-9 must be signed under penalties of perjury by the payee or by someone authorized to sign on the payee’s behalf.¹ A teenager old enough to understand what they are certifying signs the form themselves. When a child is too young to meaningfully certify the accuracy of the information, a parent or legal guardian signs as the authorized representative and writes their relationship to the child next to the signature.

The signature is not a formality. It certifies that the taxpayer identification number is correct, that the signer is a U.S. person, and that the payee is not subject to backup withholding.² A parent signing on a child’s behalf is personally vouching for every entry. False information on a signed federal tax document can trigger an accuracy-related penalty of 20% of any resulting tax underpayment, and deliberately fraudulent information can lead to a 75% penalty on the underpaid amount.³ Honest mistakes are easy to fix; the penalty framework is why care matters.

Filling In the Form Line by Line

The W-9 is a single page. For a minor, most of it fills in quickly.

Line 1, Name: the minor’s full legal name exactly as it appears on their Social Security card. A mismatch between the name and the tax ID number is one of the most common reasons for processing errors.
Line 2, Business name: leave blank unless the minor operates under a business name, which is rare.
Line 3a, Tax classification: check the box for “Individual/sole proprietor or single-member LLC.” This is the correct classification for virtually every minor.
Lines 5 and 6, Address: a permanent mailing address where the payer can send tax documents at year-end.
Part I, Taxpayer Identification Number: the minor’s Social Security Number in the boxes provided.
Part II, Certification: sign, date, and confirm the certifications. If a parent signs, note the relationship.

The requester needs the name and address exactly as entered on the W-9 to generate accurate information returns at the end of the year.⁴ Download the form directly from IRS.gov rather than a third-party version, which may be outdated.

Which Tax ID Number Goes on the Form

Most minors use their Social Security Number. For custodial accounts set up under the Uniform Gift to Minors Act, the W-9 should list the minor’s name and SSN, not the custodian’s.²

If a minor is not eligible for an SSN, the alternative is an Individual Taxpayer Identification Number. The application is Form W-7 with supporting documents to prove identity and foreign status.¹ For children under 14, the IRS waives the usual requirement that supporting documents include a photograph. A valid passport alone is sufficient; without a passport, at least two other documents from the accepted list are needed. School records work for dependents under 24, and medical records work for children under 6.⁵

Children in pending adoptions have a different option. If the Social Security Administration will not process an SSN application because the adoption is not finalized, the prospective adoptive parent can apply for a temporary Adoption Taxpayer Identification Number using Form W-7A. Once the adoption is complete, the parent must obtain an SSN for the child and stop using the ATIN.⁶

Where the Form Goes and How to Protect the Child’s SSN

The completed W-9 goes directly to the business or person who requested it. It is never mailed to the IRS or the Social Security Administration.⁴ Many requesters accept it through a secure digital portal, by fax, or by hand. Because the form carries the minor’s SSN, encrypted or secure transmission matters more than convenience. Avoid unencrypted email attachments.

Identity theft targeting children is a real concern, since a minor’s SSN can go unmonitored for years before anyone checks a credit report. Federal law allows parents to place a credit freeze on a child’s file at each of the three major credit bureaus if the child is under 16. The parent provides proof of authority, such as a birth certificate. If no credit file exists yet, the bureau creates one solely to freeze it, and the file cannot be used for credit purposes.⁷ It is worth doing any time a minor’s SSN is shared with a third party.

Keep a copy of every W-9 submitted. If the payer later generates a 1099 with incorrect information, having the original form makes it easier to resolve the discrepancy.

What Happens After the Form Is Submitted

The payer uses the information from the W-9 to prepare Form 1099 at year-end, reporting the total amount paid to the minor during the calendar year.⁴ If the payee never returns a completed W-9, the payer is required to withhold 24% of each payment as backup withholding and send it to the IRS. That money is not lost, since it gets credited when the minor’s return is eventually filed, but it can take months to recover as a refund.

If a payee writes “Applied For” in the TIN section while waiting for an SSN or ITIN, the payer has a 60-day window before backup withholding kicks in on interest and dividend payments. For other income like freelance pay, backup withholding begins immediately even while the TIN application is pending.¹

Name-and-TIN mismatches create their own problems. When the IRS detects that the name and number on a 1099 do not match its records, it sends the payer a CP2100 notice, and the payer then sends a “B notice” asking the payee to correct the information. If the payee does not respond, backup withholding must begin within 30 business days.⁸ This is why the name on Line 1 needs to match the Social Security card letter for letter.

When the Minor Actually Has to File a Tax Return

Filling out a W-9 does not by itself mean the minor owes taxes. It does mean someone will report income to the IRS under the minor’s SSN, which can trigger a filing requirement. The thresholds are lower than many parents expect.

Earned Income From Work

A dependent minor must file a federal return if their earned income (wages, freelance pay, tips) exceeds $15,750 for the 2025 tax year.⁹ Most part-time work stays below that. The lower trigger is self-employment: any minor with net self-employment earnings of $400 or more must file a return and pay self-employment tax for Social Security and Medicare, regardless of age.¹⁰ A teenager doing freelance graphic design or tutoring through an app is self-employed in the eyes of the IRS, and that $400 threshold catches a lot of families off guard.

Unearned Income From Investments or Accounts

For a dependent minor, unearned income such as bank interest, dividends, and capital gains triggers a filing requirement at just $1,350 for 2025.¹¹ If the child’s unearned income exceeds $2,700, it may be subject to the kiddie tax, which taxes the child’s investment income at the parent’s marginal rate rather than the child’s lower rate.¹² The kiddie tax applies to children under 18, children who are 18 and do not earn more than half their own support, and full-time students under 24 in the same situation.¹³

If the child’s total gross income is under $13,500 and consists only of interest, ordinary dividends, and capital gain distributions, parents can elect to report the child’s income on their own return using Form 8814 instead of filing a separate return for the child.¹² Above that amount, the child needs their own return with Form 8615 attached.

Combination Income

When a minor has both earned and unearned income, the math gets slightly more involved. A dependent must file if gross income exceeds the larger of $1,350, or earned income (up to $15,300) plus $450.⁹ These are the 2025 thresholds, which are the most recent available as of early 2026. The IRS typically publishes updated figures for the next tax year in late fall, so check IRS.gov for any 2026 adjustments before filing.

Even if a minor falls below every filing threshold, filing a return is still worthwhile when taxes were withheld from their pay or backup withholding was taken. Filing is the only way to get that money back.

1
IRS.gov. Instructions for the Requester of Form W-9 (Rev. March 2024)
2
Internal Revenue Service. Form W-9 (Rev. March 2024) – Request for Taxpayer Identification Number and Certification
3
Internal Revenue Service. Accuracy-Related Penalty
4
Internal Revenue Service. Instructions for the Requester of Form W-9 (03/2024)
5
IRS. Instructions for Form W-7
6
eCFR. IRS Adoption Taxpayer Identification Numbers
7
Federal Trade Commission. New Protections Available for Minors
8
Internal Revenue Service. Understanding Your CP2100 or CP2100A Notice
9
Internal Revenue Service. Publication 501 (2025), Dependents, Standard Deduction, and Filing Information
10
Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
11
Internal Revenue Service. Check If You Need to File a Tax Return
12
Internal Revenue Service. Topic No. 553, Tax on a Childs Investment and Other Unearned Income (Kiddie Tax)
13
IRS.gov. 2025 Instructions for Form 8615 – Tax for Certain Children Who Have Unearned Income