How to Fill Out a W-9 Correctly — Line by Line Guide

A client, platform or bank asks you for a W-9 before they can pay you. The form itself is one page and looks trivial — but a wrong box or a mismatched TIN can mean 24% of your payments withheld and sent to the IRS. This guide walks the current revision (March 2024) line by line. Ready to fill one? Use our free W-9 filler — it runs in your browser and never uploads your data.

Before you start: SSN or EIN?

Individuals fill the W-9 with their Social Security Number. Sole proprietors and single-member LLCs can use either the owner's SSN or the business EIN — if you'd rather not circulate your SSN to every client, getting a free EIN from the IRS takes minutes. Corporations and multi-member LLCs always use the entity's EIN. The rule that matters: the number must match the name on line 1 in IRS records, or the mismatch surfaces as a CP2100 notice to your client and backup withholding on your payments.

Line 1 — Name

Your full legal name exactly as it appears on your tax return. The classic trap: a freelancer with an LLC writes the LLC's name here. If your single-member LLC is a disregarded entity (the default), line 1 is your name — the LLC goes on line 2.

Line 2 — Business name

Only if different from line 1: your trade name, DBA, or disregarded LLC name. Otherwise leave it blank — don't repeat line 1.

Line 3a — Federal tax classification

Check exactly one box. The decision tree:

Freelancer / sole proprietor / single-member LLC (no election) → “Individual/sole proprietor or single-member LLC”.
LLC taxed as partnership → “Limited liability company” and enter “P”.
LLC taxed as S or C corp → “Limited liability company” and enter “S” or “C”.
Corporation / partnership / trust → the matching box.

Checking “LLC” when you haven't elected corporate taxation is the most common W-9 error — the box describes tax treatment, not legal structure.

Line 3b — Flow-through entities (new in March 2024)

Only partnerships, trusts and LLCs taxed as partnerships check this box, and only if they have foreign partners, owners or beneficiaries. If you're an individual or a single-member LLC, skip it entirely — it exists so payers know when Schedule K-2/K-3 reporting may follow.

Line 4 — Exemptions

Almost everyone leaves this blank. Exempt payee codes apply to specific entities (corporations for certain payment types, tax-exempt organizations) — if you don't know your code, you almost certainly don't have one.

Lines 5–6 — Address

The address where the requester should mail your information returns (your 1099-NEC or 1099-INT in January). Use your current mailing address and remember to send an updated W-9 if it changes.

Part I — Taxpayer Identification Number

Enter your SSN or EIN per the decision above. Double-check it digit by digit: a transposed digit is a mismatch, and mismatches are what trigger the 24% backup withholding machinery.

Part II — Certification and signature

By signing you certify, under penalty of perjury, that the TIN is correct, that you're not subject to backup withholding, and that you're a U.S. person. Don't sign a form with blanks in the required fields, and don't leave the signature empty — requesters reject unsigned W-9s, and missing certification can itself trigger withholding. An electronic signature is acceptable to most requesters.

Delivering it safely

The filled form contains your SSN. Avoid plain email attachments when you can — use the requester's secure upload link, and verify unexpected W-9 requests through a channel you already trust: fake “please send a W-9” emails are a known phishing pattern. Fill and sign the form locally with our W-9 tool, download the flattened PDF, and if you need to send supporting documents with sensitive data, redact them first.

When to send a new W-9

Name change (marriage, divorce), a new EIN, a new address, or a change in classification (your LLC elected S-corp status) — send an updated form to every active requester. Stale W-9 data is how 1099s end up going to old addresses with wrong names.

Fill out your W-9 now — free, no upload

This guide is general information, not tax advice. For your specific situation, see the official IRS instructions or consult a tax professional.