A CP2566 notice means the IRS gave up waiting for your tax return and calculated your tax for you. It used the wage and income information that employers, banks, brokers and others reported, then added penalties and interest. The result is a proposed amount due. It is not final yet, and you still have a real chance to change it. In most cases, filing your own accurate return is the best answer, because the IRS's version may not include deductions, credits or expenses you're entitled to.
Why you got a CP2566
You likely received earlier reminders, such as a CP59, CP516 and CP518, asking you to file a past-due return. When those go unanswered, the IRS can use its Automated Substitute for Return (ASFR) program. ASFR builds a return from the information returns (W-2s, 1099s and similar forms) filed under your Social Security number and proposes a tax.
Because the IRS only sees income, its calculation can leave out things that would lower your tax, such as business expenses on a Schedule C or tax credits you qualify for. Self-employed people and gig workers can be hit especially hard, since a 1099 shows gross payments, not profit.
A related version, Letter 2566R, is sent when the IRS is also holding a refund until the return issue is resolved, according to the Internal Revenue Manual.
What the CP2566 says
Look for:
- The tax year and the income the IRS used, listed by payer.
- The proposed tax, penalties and interest.
- The response date. IRS procedures for this letter give you 30 days to respond. Use the date printed on your notice.
- A response form at the end of the notice and a return envelope.
- A phone number for questions or if you think you don't have to file.
Example: finding your reply date. If your CP2566 is dated August 3, 2026, 30 days later is September 2, 2026. Always go by the response date printed on your own notice. If the date is close and you need more time, call the number on the notice before it passes.
What to do
You have two main choices, and the IRS asks you to act by the date on the notice.
Option 1: File your own return (usually best if you have deductions or credits)
- Gather your income records. Use the income listed on the notice, plus any other income you had. The IRS also says you can request a wage and income transcript (see our transcripts guide).
- Prepare the return with the deductions, credits and expenses you can support.
- File it. If the return is for one of the past 2 years, you can e-file through a provider that offers it. Otherwise, sign and date the return (both spouses if joint), complete the response form, and mail them together in the envelope provided.
- Check the details. Make sure the name, SSN and tax year on your return match the notice. Include your IP PIN if the IRS issued you one because of identity theft (each spouse's on a joint return).
The IRS will generally adjust your account to reflect the figures on your return once it processes it.
Option 2: Accept the proposed amount
Complete and return the response form at the end of the notice. Then pay in full, or look at other payment options. Before you accept, compare the IRS figures with your own records. Accepting can mean paying more than necessary.
If you think you didn't have to file
Call the number listed on your notice and have your paperwork ready.
If you disagree with the income shown
If a W-2 or 1099 listed is wrong, the IRS suggests contacting the payer for a corrected form and attaching it when you send your return.
If you can't pay
You still should file. You can set up a payment plan for what you owe. See IRS payment plans and what to do if you can't pay.
Penalties on unfiled returns add up. The failure-to-file penalty is generally 5% of unpaid tax per month or partial month, up to 25%, with a minimum 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). If you had a good reason for filing late, read about penalty relief.
An optional late-filing explanation kit is available if you want templates for explaining a late return, but the steps above are what the IRS needs.
What happens if you ignore it
If you don't respond, the IRS's next step is a Notice of Deficiency, usually the CP3219N. That is a formal "90-day letter." It gives you 90 days from its date (150 days if you're outside the United States) to either file your return or petition the U.S. Tax Court. If you do neither, the IRS assesses the tax it proposed.
Once tax is assessed and unpaid, collection begins with bills like the CP14. Unpaid balances can lead to a federal tax lien or a levy on wages or bank accounts. Even after assessment, the IRS says it is still in your interest to file your own return so it can adjust your account.
Is this notice real?
A genuine CP2566 arrives by mail and lists the specific income records the IRS used. Check it against your own W-2s and 1099s, and confirm your account through your IRS Online Account at irs.gov or by calling a number listed on irs.gov. The IRS never demands immediate payment by gift card, prepaid card or wire transfer. See our IRS scams guide.
Frequently asked questions
Is a CP2566 a bill?
Not yet. It is a proposed assessment. The tax becomes assessed only if you accept it, or if you don't respond to it and the later Notice of Deficiency.
Will filing my own return really lower the amount?
Often, if you have deductions, credits or business expenses the IRS didn't know about. It can also go the other way if you had income the IRS didn't see. Either way, your return should be complete and accurate.
Can I still file after the IRS made a substitute return?
Yes. The IRS says it is in your best interest to file your own return to claim the exemptions, credits and deductions you are entitled to, and it will generally adjust your account.
What if I'm owed a refund for that year?
You generally must file within 3 years of the return's original due date to get a refund. After that, the refund is usually lost even if you file.
Where can I get help?
VITA and TCE offer free return preparation to those who qualify. For disputes or hardship, contact a Low Income Taxpayer Clinic or the Taxpayer Advocate Service. A CPA or enrolled agent can help with several years of returns. Our unfiled tax returns guide covers catching up.
Sources
- Internal Revenue Service (IRS), "Understanding your CP2566 notice". irs.gov
- IRS, Internal Revenue Manual 5.18.1, Automated Substitute for Return (ASFR) Program (Letter 2566, 30-Day Letter). irs.gov
- IRS, "Understanding your CP3219N notice". irs.gov
- IRS, "Filing past due tax returns". irs.gov
- IRS, "Failure to file penalty". irs.gov
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.