IRS Help Center
IRS Notice & Letter Master List: What Each One Means and Your Deadline
The IRS mails hundreds of different notices and explains them one page at a time. This is the whole map in one place: 78 IRS notices and letters in a single table — the plain-English meaning, your response window, and how urgent each one really is. In a hurry? The IRS Notice Decoder is our quick triage tool; this page is the complete reference behind it.
In short: find the notice or letter number in the top right corner of page one, then look it up in the master table below. Most IRS notices allow 21 to 90 days to respond, counted from the notice date, not the day you opened the envelope.
Facts on this page last verified: July 2026.
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The Master List: 78 IRS Notices and Letters
Every notice below gets one of four urgency tiers, applied consistently:
- Info — informational; usually nothing to do
- Respond — a reply or payment is expected by the stated date
- Urgent — a late-stage warning; act now to stop escalation
- Final — levy or deficiency stage; a legal deadline is running
Jump to: CP notices · LT letters · Letters (audit, identity & enforcement)
| Notice / Letter | What it means | Response window | Urgency | Our guide |
|---|---|---|---|---|
| CP Notices — automated notices from IRS service centers | ||||
| CP01A | Your Identity Protection PIN for the coming filing season | No response needed | Info | CP01A guide |
| CP05 | Refund held while the IRS reviews your return | No response needed | Info | CP05 guide |
| CP05A | The IRS needs documents to verify your return | 30 days | Respond | CP05A guide |
| CP11 | The IRS changed your return; you now owe | 60 days to dispute | Respond | CP11 guide |
| CP12 | The IRS corrected your return; refund amount changed | 60 days to dispute | Info | CP12 guide |
| CP14 | Your first bill for unpaid taxes | 21 days | Respond | CP14 guide |
| CP21A | Change you requested created a balance due | Varies — see notice date | Respond | CP21A guide |
| CP21B | Change you requested resulted in a refund | No response needed | Info | CP21B guide |
| CP21C | Change you requested; you owe nothing | No response needed | Info | CP21C guide |
| CP21E | Audit changes created a balance due | Varies — see notice date | Respond | CP21E guide |
| CP22A | The IRS processed a change; you owe | Varies — see notice date | Respond | CP22A guide |
| CP22E | Examination changes created a balance due | Varies — see notice date | Respond | CP22E guide |
| CP23 | Estimated payments didn't match; you owe | Varies — see notice date | Respond | CP23 guide |
| CP24 | Estimated payment credits adjusted; refund coming | No response needed | Info | CP24 guide |
| CP25 | Estimated payments didn't match; balance now zero | No response needed | Info | CP25 guide |
| CP27 | You may qualify for the Earned Income Credit | Varies — see notice date | Respond | CP27 guide |
| CP32A | Your refund check expired; request a new one | Varies — see notice date | Respond | CP32A guide |
| CP49 | Your refund was applied to a tax debt | No response needed | Info | CP49 guide |
| CP53 | Direct deposit failed; a paper check is coming | No response needed | Info | CP53 guide |
| CP54 | Name and SSN on your return don't match | Varies — see notice date | Respond | CP54 guide |
| CP59 | No record of your tax return — first notice | File as soon as possible | Respond | CP59 guide |
| CP60 | A payment was removed; you owe again | Varies — see notice date | Respond | CP60 guide |
| CP62 | A missing payment was found and credited | No response needed | Info | CP62 guide |
| CP63 | Refund held because of an unfiled return | File as soon as possible | Respond | CP63 guide |
| CP71 | Annual statement of your unpaid balance | No response needed | Info | CP71 guide |
| CP71C | Annual balance reminder; can precede passport action | No response needed | Info | CP71C guide |
| CP75 | EIC audit — send documents to release your refund | 30 days | Respond | CP75 guide |
| CP79 | A tax credit was denied or reduced | No response needed | Info | CP79 guide |
| CP80 | You have a credit but no return on file | File as soon as possible | Respond | CP80 guide |
| CP81 | Refund deadline approaching; no return on file | File as soon as possible | Respond | CP81 guide |
| CP87A | Someone else claimed your dependent | Varies — see notice date | Respond | CP87A guide |
| CP88 | Refund held over an unfiled return | File as soon as possible | Respond | CP88 guide |
| CP90 | Final notice of intent to levy; hearing rights | 30 days (CDP hearing) | Final | CP90 guide |
| CP91 | Intent to levy 15% of your Social Security | 30 days | Final | CP91 guide |
| CP92 | State refund levied; you have hearing rights | 30 days (CDP hearing) | Final | CP92 guide |
| CP161 | Business balance due — tax, penalties, and interest | Varies — see notice date | Respond | — |
| CP210 / CP220 | The IRS adjusted your business tax return | Varies — see notice date | Respond | CP220 guide |
| CP215 | Civil penalty charged to your business | Varies — see notice date | Respond | CP215 guide |
| CP297 | Final intent to levy your business; hearing rights | 30 days (CDP hearing) | Final | CP297 guide |
| CP320B | Your Employee Retention Credit claim is under review | None unless the IRS asks | Info | CP320B guide |
| CP501 | Reminder: you have an unpaid balance | Varies — see notice date | Respond | CP501 guide |
| CP503 | Second reminder — no reply received, balance unpaid | Varies — see notice date | Urgent | CP503 guide |
| CP504 | Intent to levy your state refund and assets | 30 days | Urgent | CP504 guide |
| CP504B | Business version of the CP504 levy warning | 30 days | Urgent | — |
| CP508C | Tax debt certified to State Department; passport at risk | Varies — resolve the debt | Final | CP508C guide |
| CP516 | Repeated request for your unfiled tax return | File as soon as possible | Respond | CP516 guide |
| CP518 | Final notice: your tax return is still missing | File as soon as possible | Urgent | CP518 guide |
| CP521 | Installment agreement payment is due | Pay by the due date | Respond | CP521 guide |
| CP523 | The IRS intends to end your payment plan | 30 days | Urgent | CP523 guide |
| CP2000 | Income on file doesn't match your return; proposed changes | 30 days | Respond | CP2000 guide |
| CP2501 | Early inquiry about an income mismatch | Varies — see notice date | Respond | CP2501 guide |
| CP2566 | The IRS filed a return for you; proposed tax | Varies — see notice date | Urgent | CP2566 guide |
| CP3219A | Notice of Deficiency — Tax Court is the next stop | 90 days (Tax Court) | Final | CP3219A guide |
| CP3219N | Notice of Deficiency after a substitute return | 90 days (Tax Court) | Final | CP3219N guide |
| LT Letters — IRS Automated Collection System (ACS) | ||||
| LT11 | Final notice of intent to levy; hearing rights | 30 days (CDP hearing) | Final | LT11 guide |
| LT16 | Unpaid taxes or missing returns — contact the IRS | Varies — see notice date | Urgent | LT16 guide |
| LT19 | Collection reminder: pay or set up a plan | Varies — see notice date | Respond | — |
| LT38 | Collection notices are restarting; balance still due | Varies — see notice date | Respond | LT38 guide |
| LT73 | Levy issued for unpaid employment taxes; hearing rights | 30 days (CDP hearing) | Final | — |
| LT75 | A levy was issued; you have hearing rights | 30 days (CDP hearing) | Final | — |
| Letters — audit, identity & enforcement correspondence | ||||
| Letter 12C | Your return is missing a form or information | Varies — see letter date | Respond | Letter 12C guide |
| Letter 105C | Your refund claim was disallowed | Varies — appeal rights apply | Respond | Letter 105C guide |
| Letter 106C | Your refund claim was partially disallowed | Varies — appeal rights apply | Respond | Letter 106C guide |
| Letter 525 | Audit report with proposed changes (30-day letter) | 30 days | Respond | Letter 525 guide |
| Letter 531 | Notice of Deficiency after an audit | 90 days (Tax Court) | Final | Letter 531 guide |
| Letter 566 | Your return was selected for audit; send documents | Varies — see letter date | Respond | — |
| Letter 692 | Revised audit findings after your response | Varies — see letter date | Respond | Letter 692 guide |
| Letter 725-B | A revenue officer scheduled an in-person appointment | By the appointment date | Urgent | Letter 725-B guide |
| Letter 1058 | Final notice of intent to levy; hearing rights | 30 days (CDP hearing) | Final | Letter 1058 guide |
| Letter 1153 | Proposed Trust Fund Recovery Penalty against you | 60 days to protest | Urgent | Letter 1153 guide |
| Letter 3164 | The IRS may contact third parties about your taxes | No response needed | Info | Letter 3164 guide |
| Letter 3172 | Federal tax lien filed; hearing rights | 30 days (CDP hearing) | Urgent | Letter 3172 guide |
| Letter 4464C | Return under review before any refund is released | No response needed | Info | Letter 4464C guide |
| Letter 4883C | Verify your identity by phone | 30 days | Respond | Letter 4883C guide |
| Letter 5071C | Verify your identity online or by phone | 30 days | Respond | Letter 5071C guide |
| Letter 5747C | Verify your identity at an IRS office | 30 days | Respond | Letter 5747C guide |
| Letter 6173 | Virtual currency compliance — a response is required | Varies — see letter date | Respond | Letter 6173 guide |
| Letter 6174 | Virtual currency education letter; no response required | No response needed | Info | Letter 6174 guide |
Don't see your notice here? The IRS keeps its own directory at Understanding your IRS notice or letter, one notice per page — or call us at (888) 825-7779 and read us the number.
How to Read Any IRS Notice
- Find the notice or letter number. It's in the top right corner of the first page — something like "CP14," "LT11," or "LTR 1058." That number tells you exactly why the IRS wrote to you.
- Find the notice date. It sits in the same corner block. Every deadline the notice mentions runs from this date — not from the day the envelope reached your mailbox, which can be a week or more later.
- Look the number up. Use the master table above, or use our interactive IRS Notice Decoder for instant triage. If you're writing back, our free IRS letter templates cover the most common responses.
The Escalation Path: How Collection Notices Progress
For an unpaid balance, the sequence is predictable: a CP14 first bill, then the CP501 reminder, the CP503 second reminder, the CP504 intent to levy, and finally an LT11 or Letter 1058 final notice — the last stop before the IRS can levy wages and bank accounts. The final notice is also where your strongest protection lives: a Collection Due Process hearing request filed within 30 days pauses levy action while your case is heard. The full sequence, with timing between letters, is in our guides to the order of IRS collection letters and the IRS collection process step by step.
Frequently Asked Questions
How long do I have to respond to an IRS notice?
Most IRS notices give you between 21 and 90 days, and the clock starts on the notice date printed at the top of the letter, not the day you received it. Common windows: 21 days for a CP14 balance-due bill, 30 days for CP504, LT11, and CP2000, and 90 days for a CP3219A Notice of Deficiency. Some notices are informational and need no response at all.
Which IRS notices are serious?
The most serious are the final and deficiency-stage notices: CP90, CP91, LT11, and Letter 1058 (final intent to levy), CP3219A and Letter 531 (Notice of Deficiency), and CP508C (passport certification). Each starts a legal deadline, generally 30 days to request a Collection Due Process hearing on a levy notice and 90 days to petition Tax Court on a deficiency notice. Missing those windows gives up important rights.
What is the difference between a CP notice and an LT notice?
CP notices are computer-generated and sent automatically by IRS service centers; they cover everything from routine refund adjustments to collection bills. LT letters come from the IRS Automated Collection System and almost always involve an unpaid balance or a missing return. In practice, the number matters more than the prefix: an LT11 and a CP90 both mean the IRS intends to levy.
Where is the notice number on an IRS letter?
Look at the top right corner of the first page. Notices show a number like CP14 or CP2000; letters show a number like LTR 1058 or Letter 5071C. The notice date and your taxpayer ID appear in the same corner block, and on many letters the number repeats in the bottom right corner of each page.
Found Your Notice? Here's the Next Step
Knowing what the notice means is half the job; responding the right way before the deadline is the other half. Our experienced tax professionals handle IRS notices every day — get a free, confidential review of yours, and we'll tell you honestly what your options are.
Clarity Tax Relief is not affiliated with the IRS or any government agency. Response windows above reflect standard IRS practice; the controlling deadline is always the one printed on your own notice. Our guides are general information, not tax or legal advice for your specific situation; eligibility for IRS programs depends on individual facts and circumstances, and no outcome is guaranteed.
Keep reading: IRS Notice Decoder · IRS Transcript Codes · Free IRS Letter Templates · IRS Forms · IRS Help Center.