Common IRS Notice Types
Whether there's a change to your return or a balance due, make sure to respond accordingly
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The IRS sends various notices to taxpayers for different reasons, ranging from balance dues to identity verification. Understanding these notices is crucial for timely and appropriate responses.
IRS notices are identified by unique codes, such as CP or LT numbers.
Jump to insightCommon notices include those related to tax return changes and balance dues.
Jump to insightResponding promptly to IRS notices can prevent further complications.
Jump to insightWhat is an IRS notice?
From time to time, the IRS might need to contact you, and almost without exception, it will do so via U.S. mail in the form of an official notice. For most people, opening the mailbox to see a letter from the IRS is not a pleasant experience, but it’s important to know that there are a variety of reasons (outside of tax debt or an audit) the IRS might send a notice.
We’ll familiarize you with the most common types of IRS notices you might one day see in your own mailbox, and what to do (and not do!) if you receive a notice from the IRS.
Common IRS notice types
Most notices from the IRS fall into a few categories, said Divakar Vijayasarathy, CEO of DVS Advisory Group. “Most of the letters the IRS sends out in the form of notices are not adversarial in nature but merely administrative,” he said.
In general, notices from the IRS can be divided into four categories: informational, where no action is required; adjustment, when the IRS makes a change; payment or balance due, where you’ll have to take action; and warning that a lien or levy is possible.
Always fill out a change of address form when you move or relocate, even temporarily, to ensure you receive all IRS notices. The IRS isn’t required by federal law to seek your current address, only to mail notices to your last listed address on file.
In most cases, Vijayasarathy said, the notices fall under the first two categories. Common IRS notices include:
- Request for additional information
- Notification of an adjustment made to a tax return
- Tax due or refund
- Enforcement action, such as a lien or levy
- Confirmation of compliance or closing of an ongoing issue
Assuming the IRS has your current and correct address on file, it’s easy to spot an IRS notice. They arrive in a white envelope that’s clearly marked with the official title and emblem of the IRS.
Inside, you’ll find a letter with a particular code listed on the top righthand side, often a letter and number combination (like CP503). For example, CP means “Computer Paragraph.” These are automated IRS notices. LT, on the other hand, means “Letter Template.” They typically represent follow-up communication or requests for urgent action.
Which notices does the IRS commonly send out?
We’ve compiled a comprehensive list of notices the IRS often sends, and what each one means. Regardless of type, the best way to handle an IRS notice is to open it, understand it and respond to it in a timely manner.
| Notice or letter | Official name | What it means |
|---|---|---|
| CP2000 | Notice of mismatch | Issued when income reported on W-2s or 1099s doesn’t match the income reported on your tax return |
| CP12 | Math correction notice | Sent when the IRS corrects a calculation error, often changing the amount of your refund |
| CP14 | Balance due notice | Notifies you that taxes are owed after the IRS processes your return |
| CP501 / CP503 / CP504 | Progressive reminders for unpaid balances | A series of escalating notices sent before the IRS may take enforced collection action, such as wage garnishment |
| CP21 | Adjustment to a tax return | Indicates the IRS adjusted your tax return for one or more reasons |
| Letter 12C | Missing information or forms | Alerts you that required information or forms were missing from your tax return |
| CP23 | Estimated tax payment discrepancy, balance due | The IRS found a difference between the estimated tax payments you claimed and what it has on record, resulting in a balance due |
| CP45 | Reduced amount applied toward estimated tax | The IRS reduced the portion of your refund applied to next year’s estimated taxes because the full amount wasn’t allowable |
| CP79 | Earned Income Credit eligibility requirement | Indicates that an Earned Income Credit you claimed was reduced or denied |
| CP2000 | Notice of underreported income | Proposes changes to your return based on income the IRS believes wasn’t fully reported |
| Letter 531 | Notice of deficiency | States the IRS has determined you owe additional tax, penalties, or interest and gives you the right to petition the Tax Court |
| Letter 525 | Examination report | Explains audit findings and gives you 30 days to agree with or appeal the IRS’s determination |
How to respond to IRS notices
First — don’t panic! While receiving a notice from the IRS isn’t ideal, it’s usually not quite as scary as most people think. Open the notice and read it carefully. The notice will clearly state the issue and present the information and any action items you might need to handle.
If you think the notice is in error, or if you’d like further clarification, call the IRS directly using the number provided in the notice. If you’re facing a difficult issue, the IRS will provide you with a case manager who can answer any questions you may have.
Avoiding notices from the IRS is never the right answer, said Vijayasarathy, because they don’t go away. “The IRS will continue to send notices and can even garnish your wages if you owe money and refuse to communicate with the IRS,” he warned.
» COMPARE: 3 best tax relief companies
Dos and don’ts if you receive an IRS notice
Vijayasarathy summarized what to do if you receive a letter from the IRS and what you shouldn’t do.
What you should do:
- Read the notification carefully.
- Check whether it’s an action item.
- Compare information in the notice with your tax return, if applicable.
- Respond within the stated deadline, even if you don't agree.
If you don’t understand the issue, consult a tax professional who can help you navigate it. If you had someone prepare your taxes for you, they might be a good point of reference. Similarly, tax preparation software, like TurboTax, offers live chat support.
What you should NOT do:
- Ignore the notice.
- Call the IRS without a basic understanding of the notice.
- Send money to the IRS without verification of the amount due.
- Assume the notice means an audit.
Resources for understanding IRS notices
Resources are available that can help demystify IRS notices. First, Vijayasarathy suggested heading to the IRS website at www.irs.gov and entering the notice number. You can find this on the top right-hand corner of the IRS notice. The IRS website features a generous amount of content for all topics, including how to decode notices.
You can also access your personal IRS online account to find further information. You can see notices, check balances, make payments to the IRS and upload any requested documents.
A tax professional can help you navigate this process, which can potentially eliminate the need to contact the IRS by phone altogether, which can be an arduous process.
» EXPLORE: What you should know before choosing a tax preparer
FAQ
What are the four types of IRS notices?
The four types are informational, adjustment, notice of payment or balance due, and a warning that a lien or levy is possible.
How many types of notices are there?
There’s a long list of notices the IRS might send for any given reason. That’s because some notices are general, while others are specific to a situation. But there’s a short list of IRS notices that are common. An IRS notice doesn’t automatically mean there’s a major issue.
How many notices does the IRS give you?
If the IRS is contacting you with minor information that doesn’t require action on your part, they’ll likely only send one notice. However, if you owe money, the IRS will send several notices over the span of many months, which increase in urgency if you fail to respond.
Expect at least three or four IRS notices before your wages are garnished as a result of money you owe the IRS.
Can you view IRS notices online?
Yes. You can view IRS notices online. Navigate to irs.gov and go to the top right-hand side of the screen, where it says sign in. You can access either individual or business tax information once you create a username and password.
Article sources
ConsumerAffairs writers primarily rely on government data, industry experts and original research from other reputable publications to inform their work. Specific sources for this article include:
- IRS, “When an IRS Letter Arrives, Taxpayers Don’t Need to Panic, but They Do Need to Read It.” Accessed Jan. 21, 2026.
- IRS, “Understanding Your IRS Notice or Letter.” Accessed Jan. 25, 2026.
- TaxAct, “Audit Assistant IRS Notice Listing.” Accessed Jan. 21, 2026.
