Got a letter from the IRS this fall? Start here.
Most IRS letters are about something specific and fixable. Every one of them has a date on it, and that date matters more than anything else on the page. Here is what to do, in order.
1. Make sure it is real.
Find the notice number in the top or bottom right corner (it starts with CP, LT or Letter). Type it into our IRS Notice Library. The IRS says that if the letter does not appear in its search, or looks suspicious, you should call the IRS at 800-829-1040. The IRS starts contact by mail; do not click links or scan codes in a text or email that claims to be the IRS.
2. Find the date.
The IRS's own instruction is to review the letter carefully, keep it, and if it asks you to respond, act by the due date. Write that date on your calendar today.
3. Know which clock you are on.
Different letters run on different clocks. These are set by federal law, not by the IRS's preference:
| If your letter is… | Your clock | What it protects | Law |
|---|---|---|---|
| A math or clerical error notice (the IRS changed your return) | 60 days to ask the IRS to reverse the change | If you ask in time, the IRS must abate the assessment and use normal procedures instead | IRC §6213(b)(2)(A). |
| A CP2000 (your income didn't match what others reported) | Reply by the date on the notice | It is a proposal, not a bill. If you don't reply, the IRS may send another notice and a bill | IRS.gov CP2000 page. |
| A Notice of Deficiency ("90-day letter") | 90 days (150 if addressed outside the U.S.) to petition the Tax Court | Your right to go to court before paying | IRC §6213(a). |
| A final notice of intent to levy with hearing rights (e.g., LT11, Letter 1058) | 30 days to request a Collection Due Process hearing | An independent Appeals hearing before the levy | IRC §6330(a). |
New this year: clearer error notices.
A federal law signed November 25, 2025, the IRS Math and Taxpayer Help Act, changes math-error notices sent after November 25, 2026. Those notices must explain the error in plain language, name the line of your return, show an itemized computation of the changes, include the phone number for the automated transcript service, and print the date you have to request a reversal in bold, 14-point type next to your address on page one. If you receive one of these this winter, that bold date is your 60-day deadline.
4. Decide: agree, disagree, or can't pay.
Per the IRS: if you agree, take the requested action; you don't need to reply unless asked. If you disagree, follow the notice's dispute instructions and send copies of your documents, and reply by the due date to keep your appeal rights. If you owe and can't pay it all, pay what you can by the due date to reduce interest and penalties.
5. Get your transcript, then get a second set of eyes.
Your IRS transcript shows what the IRS actually has on file. Pull it yourself free at IRS.gov. Then find your notice in our IRS Notice Library, or call (817) 214-4014.
For reporters
Ebot Mbi, CPA (Texas #127163), is enrolled to practice before the Internal Revenue Service and has represented taxpayers in IRS collection and examination matters for more than 20 years. He is available for comment on IRS notices, collection, and the MATH Act notice changes. (817) 214-4014.
This page is general information, not tax advice, and does not create a CPA–client relationship. Last reviewed: October 16, 2026. Sources: 26 U.S.C. §§6213, 6330; Pub. L. 119-39; IRS.gov, "Understanding your IRS notice or letter" and "Understanding your CP2000 series notice".