A CP518 is the IRS's final reminder that it still has no record of a tax return it believes you should have filed for a prior year. Before this, you probably received a CP59 and a CP516. The CP518 is more serious because the next step can be the IRS calculating your tax for you, often in a way that costs you more. The good news is that you can still take control: file the return, or tell the IRS why you don't need to.
Why you got a CP518
The IRS has income records for you, such as W-2s or 1099s, but no return for that year, and earlier notices didn't resolve it. Common reasons:
- The return was never filed.
- You filed, but the IRS doesn't show it, for example because an e-filed return was rejected or a paper return was lost or filed under a different name, number or year.
- You responded to earlier notices, but your response hasn't been processed yet.
- You weren't required to file, but never told the IRS.
What the CP518 says
Look for:
- The tax year the IRS says is missing.
- Your name and Social Security number as the IRS has them.
- The address and fax number for your response.
- A toll-free phone number for questions or to discuss disagreement.
- The notice date. The IRS asks you to respond immediately.
According to the Internal Revenue Manual, a CP518 also serves as advance notice that the IRS may contact third parties, such as payers, to verify your income information.
What to do
The IRS lays out three ways to respond.
- If you haven't filed: file your tax return along with a completed Form 15103, Form 1040 Return Delinquency, explaining why you're filing late.
- If you already filed: complete Form 15103 to say so. The IRS also asks you to send a signed, dated copy of the return with the form if it's been more than 8 weeks since you filed. Make sure the name, SSN and year on the return match the notice.
- If you don't have to file: complete Form 15103 explaining why.
- Send your response to the address on the notice, or fax it to the number on the notice. If you're only sending Form 15103 to explain why you don't have to file, you can submit it online through your IRS Online Account.
- Keep copies and proof of when you mailed or faxed it.
Filing electronically. The IRS accepts e-filed returns for the 2 most recent prior years, but you need an e-file provider that offers it. Older returns go on paper to the address on your notice.
If you just filed. The IRS says you don't have to do anything if you filed within the last 8 weeks.
If you disagree. Call the toll-free number on your notice with your notice and account information ready, or respond with Form 15103.
If you can't pay. File your return anyway. You can request a payment plan to pay over time. See IRS payment plans and what to do if you can't pay.
If you need income figures. You can get a wage and income transcript through your IRS Online Account or by Form 4506-T, or ask your employer or payer. Our unfiled tax returns guide walks through catching up.
Filing late with a short, honest explanation on Form 15103 is far better than not filing. If something serious, such as illness or a disaster, kept you from filing, say so. You may be able to ask for penalty relief later. An optional late-filing explanation kit is available if you want help organizing that explanation.
What happens if you ignore it
The IRS says that if it doesn't hear from you:
- It may determine your tax for you. Under its Automated Substitute for Return (ASFR) program, the IRS prepares a return from the income reports it has and mails a proposed assessment, usually a CP2566, which gives you 30 days to respond. That calculation may not include deductions and credits you could claim.
- Penalties and interest may keep growing. The failure-to-file penalty is generally 5% of unpaid tax per month or partial month, up to 25%, with a minimum penalty for returns more than 60 days late ($525 or 100% of the unpaid tax, whichever is less, for returns due after December 31, 2025, per the IRS).
- Refunds may be delayed. The IRS holds refunds when returns are past due. And if you are owed a refund, you generally must file within 3 years of the due date to claim it.
If the IRS assesses tax and you don't pay, the balance goes to collection, starting with a bill such as the CP14, and can lead to a federal tax lien or levy.
Is this notice real?
A real CP518 comes by U.S. mail and names a specific tax year. To check, sign in to your IRS Online Account through irs.gov, review your account transcript, or call the IRS at a number found on irs.gov. The IRS does not start contact by email, text or social media and never asks for gift cards. See our IRS scams guide.
Frequently asked questions
Is a CP518 the last notice before the IRS takes action?
It is the IRS's final reminder to file. After it, the IRS may prepare a substitute return and propose an assessment. You can still file your own return at that stage, but it's easier to respond now.
What is Form 15103?
Form 15103, Form 1040 Return Delinquency, is the IRS's response form for unfiled-return notices. You use it to explain why you're filing late, that you already filed, or why you don't have to file.
Can I respond online?
Partly. The IRS says that if you're only sending Form 15103 to explain why you don't have to file, you can submit it through your IRS Online Account. Returns themselves are mailed or faxed per the notice, or e-filed if the year is eligible.
Do I need a tax professional?
Not always. Many people can file one late return on their own or with free help from VITA or TCE. If you have several unfiled years, a business, or a large balance, a CPA, enrolled agent or Low Income Taxpayer Clinic can help. Avoid companies that promise to settle debts for "pennies on the dollar."
What if I'm due a refund?
File as soon as possible. You generally must file within 3 years of the return's due date to claim a refund, and the IRS may hold other refunds until the past-due return is filed.
Sources
IRSV.com is an independent guide and is not affiliated with the IRS. This page is general information, not tax or legal advice. Rules change; confirm details on IRS.gov or with a tax professional. Found an error? Tell us.