# CP518 notice: the final reminder to file a missing return Source: https://backtaxesdesk.com/irs-notices/irs-notice-cp518 Publisher: Back Taxes Desk (backtaxesdesk.com), independent editorial site Topic: IRS Notices and Letters Last updated: 2026-09-18 > A CP518 notice is the IRS's final reminder that it still has no record of a prior-year tax return from you. Respond now by filing the return with Form 15103, or by sending Form 15103 alone if you already filed or were not required to. If you ignore it, the IRS may figure your tax for you, and penalties and interest keep growing. ## Key facts - What it is: Final reminder that a prior-year return is missing - Form to include: Form 15103, Form 1040 Return Delinquency - Filed in the last 8 weeks: No action needed - E-file allowed for: The two most recent prior years ## What a CP518 notice means A **CP518 notice** is the last letter in the IRS's reminder series about an unfiled individual return. The wording is direct: this is your final reminder, and the IRS still shows no return for the year listed. Earlier letters, starting with the [CP59](https://backtaxesdesk.com/irs-notices/irs-notice-cp59), asked the same question. The word final matters. The next step the notice warns about is action the IRS takes on its own, such as preparing a return for you from the income reports it holds. You still control the outcome if you respond now. ## CP518 vs CP59: what changes at the final reminder Both notices concern the same missing return, and both use Form 15103 for explanations. The difference is urgency and what the IRS asks you to send. | Point | CP59 | CP518 | | --- | --- | --- | | Position in series | First notice of a missing return | Final reminder | | What to send if you must file | The return | The return plus a completed Form 15103 explaining why it is late | | If you already filed or need not file | Explain, with Form 15103 if you think it is an error | Send Form 15103 | | Stated consequence | Lost refunds, lost credits, growing penalties and interest | IRS may figure your tax; refunds may be delayed or lost | How a CP518 compares with a CP59 If you already answered an earlier notice, send the same material again along with the date you first sent it. ## What the IRS may do next after a CP518 notice The CP518 lists three results if you do not respond: the IRS may figure your tax for you, penalties and interest keep adding up, and any refund you are owed may be delayed or lost. The first of these is called a [substitute for return](https://backtaxesdesk.com/unfiled-returns/irs-substitute-for-return). A substitute return uses the W-2s, 1099s and similar reports the IRS has on file. It may leave out deductions, credits and filing status choices you are entitled to, so the tax it shows is often higher than a return you prepare. Filing your own return later usually replaces those figures, but by then penalties and interest have been running on the larger amount. ### A worked example of the refund clock Refunds have a hard limit. You must claim a refund within three years of the return's due date. A 2023 return was due April 15, 2024, so the last day to claim a 2023 refund is April 15, 2027. If a CP518 is about 2023 and you were owed money, filing before that date protects the refund; after it, the money is lost. ## How to respond to a CP518 notice Choose the path that fits, and send your response to the address on the notice or by the fax number printed on it. If you are only explaining why you do not have to file, you can submit Form 15103 through your IRS online account. 1. If you filed within the last eight weeks, no action is needed. 2. If you filed earlier, complete Form 15103 saying so and attach a copy of the signed return and proof of filing. 3. If you were not required to file, complete Form 15103 and give the reason, such as income below the filing requirement. 4. If you have not filed, prepare the return, complete Form 15103 explaining why it is late, and send both together. 5. If you owe and cannot pay in full, pay what you can and request a payment plan. The IRS accepts e-filed returns for the two most recent prior years through authorized e-file providers, though not every tax product offers it. Older returns go on paper. If you are missing income records, see [how to file unfiled tax returns](https://backtaxesdesk.com/unfiled-returns/how-to-file-unfiled-tax-returns) for getting wage and income transcripts. > **Other years may be missing too:** If you skipped more than one year, file each missing return, not only the one named on the notice. You must be current on filing before the IRS will approve a payment plan. Our [unfiled tax returns guide](https://backtaxesdesk.com/unfiled-returns) covers how to prioritize them. ## Is an IRS notice CP518 a scam? A real CP518 arrives by mail with the notice number in a corner of the page, and it never asks for payment by gift card or to a private account. You can confirm it through your IRS online account, which shows certain notices, rather than trusting contact details in an unexpected call, text or email. An authorized representative, a Low Income Taxpayer Clinic or the Taxpayer Advocate Service can also help you respond. Other notices in this series are listed in our [IRS notices guide](https://backtaxesdesk.com/irs-notices). ## Step by step 1. **Check your filing status.** Decide whether you filed recently, filed earlier, were not required to file, or still need to file. 2. **Complete Form 15103.** Explain your situation on Form 15103, Form 1040 Return Delinquency. 3. **File the return if needed.** Prepare the missing return and send it with Form 15103 to the address or fax on the notice. 4. **Arrange payment.** Pay what you can and request a payment plan for any balance. ## Common questions ### What is a CP518 notice? It is the IRS final reminder that it has no record of a prior-year tax return from you. It asks you to file now or explain why you do not need to, using Form 15103. ### How is CP518 different from CP59? A CP59 is the first notice about a missing return. A CP518 is the final reminder, and it asks you to include Form 15103 even when you send the return. ### What happens if I do not respond to a CP518? The IRS may figure your tax for you from the income reports it holds, penalties and interest keep growing, and any refund you are owed may be delayed or lost. ### Can the IRS file a return for me after a CP518? Yes. It can prepare a substitute for return using third-party income data. That version may omit deductions and credits, and you can replace it by filing your own return. ### Do I need to respond to a CP518 if I just filed? No action is needed if you filed within the last eight weeks. If it has been longer, send Form 15103 with a copy of the return and proof of filing. ## Sources - [Understanding your CP518 notice](https://www.irs.gov/individuals/understanding-your-cp518-notice) - [Understanding your CP59 notice](https://www.irs.gov/individuals/understanding-your-cp59-notice) - [Filing past due tax returns](https://www.irs.gov/businesses/small-businesses-self-employed/filing-past-due-tax-returns) - [Time you can claim a credit or refund](https://www.irs.gov/filing/time-you-can-claim-a-credit-or-refund)