What does my IRS notice mean?
Enter the code printed on your IRS notice or letter, such as CP2000, CP14 or LT11, to see what it means in plain English, how serious it usually is and how long you typically have to respond. Add the notice date to count the days. The date printed on your notice always controls.
Decode your notice
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Your result
Enter a notice or letter code to see what it means, how urgent it is and what to do next.
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Which IRS notices does the decoder cover?
These 40 notices and letters are covered. Select a code for its full page, or browse all related IRS notice pages. Severity is RAHA Financials' own 1 to 5 rating of how urgent a notice usually is (1: informational; 5: urgent: rights or deadlines at stake), not an IRS classification.
| Code | What it is | Severity | Typical response window |
|---|---|---|---|
| CP14 | Balance due (first bill) | 3 of 5 | Date printed on notice |
| CP501 | Reminder of unpaid taxes | 3 of 5 | Date printed on notice |
| CP503 | Second reminder of unpaid taxes | 4 of 5 | Date printed on notice |
| CP504 | Notice of intent to levy | 4 of 5 | 30 days from the notice date |
| LT11 | Final notice of intent to levy | 5 of 5 | 30 days from the notice date |
| CP90 | Final notice of intent to levy | 5 of 5 | 30 days from the notice date |
| CP91 | Intent to levy Social Security benefits | 5 of 5 | Date on notice (typically 30 days) |
| LT16 | Collection letter for taxes or missing returns | 4 of 5 | No fixed deadline |
| CP71C | Annual reminder of a balance due | 3 of 5 | Date printed on notice |
| CP521 | Installment payment reminder | 2 of 5 | Date printed on notice |
| CP523 | Intent to end your installment agreement | 4 of 5 | 30 days from the notice date |
| Letter 3172 | Federal tax lien filed, right to a hearing | 5 of 5 | Date printed on notice |
| CP161 | Unpaid balance due (business) | 3 of 5 | Date on notice (typically 10 days) |
| CP215 | Civil penalty charged | 3 of 5 | Date printed on notice |
| CP162 | Penalty for not e-filing a return | 3 of 5 | Date printed on notice |
| CP2100 | Payee TIN mismatch and backup withholding | 3 of 5 | 15 business days from the notice date |
| CP2000 | Proposed changes for unreported income | 3 of 5 | Date on notice (typically 30 days) |
| CP2501 | Income mismatch with third-party reports | 3 of 5 | Date printed on notice |
| CP3219A | Statutory notice of deficiency | 5 of 5 | Date on notice (typically 90 days) |
| Letter 525 | 30-day letter proposing audit changes | 4 of 5 | 30 days from the notice date |
| Letter 566 | Audit by mail, documents requested | 4 of 5 | Date printed on notice |
| CP75 | EIC audit, documents requested | 4 of 5 | Date printed on notice |
| CP05 | Refund held while IRS verifies your return | 2 of 5 | No fixed deadline |
| CP59 | No record of your prior-year return | 3 of 5 | No fixed deadline |
| CP11 | Math error changed what you owe | 3 of 5 | Date on notice (typically 60 days) |
| CP12 | Math error changed your refund | 2 of 5 | Date on notice (typically 60 days) |
| CP13 | Math error correction, no balance due | 2 of 5 | Date on notice (typically 60 days) |
| CP10 | Correction reduced your estimated tax credit | 2 of 5 | Date printed on notice |
| CP24 | Estimated tax payments didn't match | 2 of 5 | Date printed on notice |
| CP49 | Refund applied to a tax debt | 2 of 5 | No fixed deadline |
| CP60 | Misapplied payment removed, balance due | 3 of 5 | Date printed on notice |
| CP22A | IRS changed your return, balance due | 3 of 5 | Date printed on notice |
| CP87A | Dependent claimed on another return | 2 of 5 | No fixed deadline |
| CP79 | Show eligibility before claiming credits | 2 of 5 | No fixed deadline |
| CP09 | You may qualify for the Earned Income Credit | 2 of 5 | 30 days from the notice date |
| CP53E | Refund held, bank account details needed | 2 of 5 | 30 days from the notice date |
| Letter 5071C | Verify your identity (online option) | 3 of 5 | No fixed deadline |
| Letter 4883C | Verify your identity by phone | 3 of 5 | No fixed deadline |
| Letter 12C | More information needed for your return | 3 of 5 | Date on notice (typically 20 days) |
| CP575 | EIN confirmation notice | 1 of 5 | No fixed deadline |
"Date printed on notice" means the IRS gives no fixed number of days that we can count for you. Always check your own notice.
How does the IRS Notice Decoder work out my deadline?
The decoder matches the code you type against a list of 40 IRS notices and letters. Each entry was checked against IRS.gov pages, IRS publications and the Internal Revenue Manual (see each notice page for its sources). It accepts common ways of writing a code, such as "cp 2000", "CP-2000", "LTR 525" or "Letter 1058", and a few variants the IRS explains on the same page as one of ours (for example CP2100A, which shares a page with CP2100). If a code isn't on the list, the decoder says so and doesn't guess.
Each notice falls into one of four deadline types:
- Counted from the notice date. The IRS measures the window from the date of the notice (for example 30 days for CP504). Respond-by date = notice date + the number of days. We show how many days are left, or how many days overdue it is.
- Date printed on the notice, with a typical window. The IRS tells you to respond by the date on the notice, and an IRS source gives the usual number of days (for example 30 days for CP2000, or 60 if you live outside the United States). We show an approximate date, but the date printed on your notice controls.
- Date printed on the notice only. The IRS gives no fixed number of days, so we don't estimate one. Letter 3172 is in this group because its 30 days are counted from the end of a 5-business-day period after the lien is filed, not from the letter date.
- No fixed deadline. The notice is informational or asks you to act without a set window. We explain what, if anything, to do.
Calendar days vs. business days. Windows are counted in calendar days unless the IRS says business days. For CP2100 the window is 15 business days, so the decoder skips Saturdays, Sundays and federal legal holidays. If you received a CP2100 later than its date, Publication 1281 counts from the date you received it.
Weekends and holidays. IRC §7503 moves a tax filing or payment deadline that falls on a weekend or legal holiday to the next business day. We don't apply that rule to notice response windows. We show plain calendar days from the notice date, because the date printed on your notice is the one the IRS uses. If a date we show differs from your notice, follow the notice.
Severity is our own 1 to 5 rating of how urgent a notice usually is, based on the dataset's reason for each notice. It is not an IRS classification.
What the decoder can't know: the exact amounts, tax years or options on your notice, whether you've already responded, or whether a later notice has replaced this one. Read your notice in full.
Worked examples
Deadlines as of September 23, 2026, produced by running the decoder on these notice dates.
| Notice and date printed on it | How the deadline is set | Decoder result |
|---|---|---|
| CP2000 dated September 1, 2026 | Date on notice (typically 30 days) | About October 1, 2026 (estimate) |
| CP504 dated September 10, 2026 | 30 days from the notice date | Respond by October 10, 2026 (17 days left) |
| CP2100 dated September 4, 2026 | 15 business days from the notice date | Respond by September 28, 2026 (5 days left) |
| LT11 dated August 14, 2026 | 30 days from the notice date | Respond by September 13, 2026 (10 days overdue) |
These examples are generated by running this calculator's own code with the figures on this page, so they always match what the tool shows.
Frequently asked questions
Is this IRS letter real or a scam?
The IRS says it normally contacts you the first time by mail delivered by the U.S. Postal Service, and that a social media direct message is never from the IRS. To check a letter, search for its notice or letter code on IRS.gov. The IRS says that if the letter doesn't appear in its search or looks suspicious, you should call the IRS using the phone number published on IRS.gov. Use phone numbers and web addresses you find on IRS.gov yourself, not ones from an unexpected email, text or call. For example, the IRS says it notifies you of an audit by mail (see Letter 566), and for identity verification it asks you to type irs.gov/verifyreturn yourself rather than follow a link (see Letter 5071C).
Do I have to reply to every IRS notice?
No. The IRS says to review each notice carefully and keep it for your records. If you agree with it, you generally don't need to reply unless the notice specifically asks you to. If it asks you to respond or pay, act by the due date. If you disagree, follow the instructions in the notice, include copies of your documents and reply by the due date to protect your appeal rights.
What if I missed the deadline on my notice?
Contact the IRS as soon as you can, using the number on your notice, and respond anyway. What you lose depends on the notice. For example, after the hearing deadline on LT11 or Letter 3172 you may still ask for an "equivalent hearing" within a longer period, but without Tax Court review. For math-error notices such as CP11, CP12 and CP13, missing the date can mean losing formal rights to have the change reversed. The Tax Court petition deadline on CP3219A can't be extended. Each notice page explains what happens if you miss or ignore that notice.
Can I get more time to respond to an IRS notice?
Sometimes, but ask before the deadline. For CP2000, the IRS says you can call the number on the notice or request an extension by mail or fax before the response date. For audits by mail such as Letter 566 and Letter 525, the IRS says it can ordinarily grant a one-time automatic 30-day extension if you fax or mail a request. Some deadlines can't be extended: the Tax Court petition deadline on CP3219A, and a phone call does not extend the hearing deadline on Letter 3172.
Why does the decoder tell me to use the date printed on my notice?
For many notices the IRS sets the deadline as "the date shown on your notice" rather than a fixed number of days. Some windows are also counted from something other than the notice date, such as the date you received it or the end of another period. Where an IRS source gives a typical window, we show an approximate date. The date printed on your notice is always the one to follow.
What does the severity rating mean?
It is RAHA Financials' own 1 to 5 rating of how urgent a notice usually is, not an IRS classification. 1 is informational (for example CP575, which confirms an EIN). 5 means enforcement may be close or a deadline can cost you rights (for example LT11, CP90 or CP3219A). Your own notice may be more or less urgent depending on your situation.
My notice code isn't in the decoder. What should I do?
The decoder covers 40 common notices and letters, and it won't guess at codes it doesn't know, because similar codes can mean very different things. Check the code printed on your notice, then look it up on the IRS "Understanding your IRS notice or letter" page, or call the number printed on the notice.
Does the decoder store my notice details?
No. The decoder runs in your browser and asks only for the notice code and date. It never asks for your name, Social Security number or amounts. The code and date are added to the page address so you can bookmark or share the result.
Disclaimer: This tool provides general estimates for educational purposes and is not tax, legal or accounting advice. Results depend on facts not captured here. Consult a qualified professional before acting.
Sources
- IRS: Understanding your IRS notice or letter: https://www.irs.gov/individuals/understanding-your-irs-notice-or-letter
- IRS: How to know it's really the IRS calling or knocking on your door: https://www.irs.gov/help/how-to-know-its-the-irs
- IRS Publication 1281 (CP2100 business days): https://www.irs.gov/pub/irs-pdf/p1281.pdf
