IRS notices explained, one by one
Find the number in the corner of your letter, then open its page below. Each of these 19 notices is summarised from the IRS's own page for it, with what it means, what to do, and what happens if you disagree.
Notices for individuals and sole proprietors
| Notice | What it means |
|---|---|
| CP2000 | The IRS is proposing changes to your tax return because income or payment information it received from third parties does not match what you reported. It is not a bill, but you may need to respond. |
| CP14 | The IRS says you owe money on unpaid taxes. The notice shows the amount owed and how to pay it. |
| CP501 | This is a reminder that you still owe a balance on one of your tax accounts. The IRS hasn't received your payment or a response to an earlier notice. |
| CP503 | This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices. |
| CP504 | This is a Notice of Intent to Levy under Internal Revenue Code section 6331(d) and a final reminder that the IRS may levy your wages, bank accounts, or state tax refund for an unpaid balance. The IRS will also begin searching for other assets to levy. |
| LT11 | The IRS has not received payment for overdue taxes and intends to seize your property or rights to property. You must contact the IRS immediately. |
| CP90 | The IRS intends to levy (seize) certain assets to collect unpaid taxes. The notice also tells you that you have the right to a Collection Due Process hearing. |
| CP11 | The IRS corrected one or more mistakes on your tax return, and as a result the amount you owe has changed. |
| CP12 | The IRS corrected one or more mistakes on your tax return, and you are now due a refund or your original refund amount has changed. |
| CP23 | The IRS corrected your return because the estimated tax payments you reported didn't match the payments posted to your account, and your balance due changed as a result. |
| CP24 | The IRS corrected your return because the estimated tax payments you reported didn't match the payments posted to your account, and you may now have a credit. |
| CP49 | The IRS used all or part of your refund to pay a tax debt you owe. |
| CP59 | The IRS has no record that you filed your prior-year personal tax return, and you need to file it right away or explain why you don't have to. |
| CP3219A | The IRS is proposing a change to your income tax because income information from employers, banks, or others differs from what you reported. It is a proposed change, not a bill or audit, and explains how to agree, disagree, or petition the U.S. Tax Court. |
| CP161 | The IRS is telling you that your account has an unpaid balance from your tax return, and the notice shows how that amount was calculated. |
Notices for businesses and employers
| Notice | What it means |
|---|---|
| CP162 | The IRS charged your partnership or corporation a penalty because the return was not filed electronically as required. |
| CP2100 / CP2100A | As a payer who filed information returns such as 1099s, you included payee names or taxpayer identification numbers (TINs) that were missing, obviously incorrect, or didn't match IRS records. You may need to start backup withholding. A CP2100 goes to payers with 50 or more such returns, and a CP2100A to payers with fewer than 50. |
| CP575 | The CP575 is a digital notice confirming your business's Employer Identification Number (EIN). It's available only through the Business Tax Account and can be used in place of the original CP575A-J notice or Letter 147C. |
| CP136 | Your Form 941 tax deposit schedule for next year may change. The IRS bases it on the total tax you reported on Forms 941 during the lookback period (the four prior quarters). |
Before you rely on any of this
Every page links the IRS page it was built from and shows the date we last checked it. Your notice is the authority on your amounts and deadlines. Coverage is growing: a notice that is not listed here has simply not been added yet.
Related
- Quarterly estimated tax — avoid underpayment notices next year.
- 1099 filing — the forms behind most income-mismatch notices.
- 2025 and 2026 tax changes
Frequently asked questions
Where do I find the notice number?
The IRS prints the notice or letter number in the top or bottom right corner of the letter, for example CP2000 or LTR 147C. Match that number to the list on this page.
Is a letter from the IRS always genuine?
Not always. The IRS starts most contact by mail, not by phone, email or text. If you are unsure, sign in to your IRS online account to see whether the notice is there, or call the number listed on IRS.gov rather than one on the letter.
Should I pay before I am sure the notice is right?
Read the notice and compare it with your records first. Each notice page here explains what the IRS says to do if you agree and if you disagree. Many notices give you a response date that matters more than paying immediately.
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Authoritative sources
US tax rules change every filing season. Always verify the current position with the official sources below before filing.
- IRS — irs.govInternal Revenue Service. Forms, publications, due dates, and current-year thresholds for federal income tax, payroll tax, and 1099 reporting.
- IRS — Forms & InstructionsCanonical PDF forms (W-4, W-9, 1099-NEC, 1040-ES, 941, 940, W-2, W-3) with current-year instructions.
- SSA — Business Services OnlineSocial Security Administration portal for W-2 / W-3 e-filing, EIN verification, and AccuWage validation.
- Streamlined Sales Tax — streamlinedsalestax.orgMulti-state Streamlined Sales and Use Tax Agreement (SSUTA) — registration in 24 SST member states with one application.
- Tax Foundation — Sales Tax & NexusIndependent state-by-state research on sales tax rates, economic nexus thresholds, and franchise / margin tax structures.
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