The IRS sends letters for specific reasons tied to your tax account

The IRS mails letters when something on your tax return needs attention, when you owe money, when they need more information from you, or when they are notifying you of a change to your account. The letter itself will state the reason in the opening section — usually within the first paragraph. Common reasons include a math error on your return, a missing document, income the IRS has a record of that you did not report, a refund status update, or a balance due notice.

The letter is not automatically a problem. Many IRS letters are routine notifications. Some require you to respond; others are informational only. The key is reading the letter carefully to understand what action, if any, you need to take and by when.

Key Takeaways

  • Every IRS letter states its reason in the opening section and includes a specific notice number that identifies what triggered the mailing.
  • The letter will tell you whether you need to respond, and if so, the deadline and how to respond (by mail, phone, or online).
  • If you do not understand the reason or disagree with what the IRS says, the letter includes contact information and instructions for requesting an explanation or filing a response.
  • Ignoring an IRS letter does not make it go away; the IRS will continue collection or enforcement action if you do not respond by the deadline.
  • You can call the IRS phone number on the letter, mail a response, or use the IRS website to check your account status and respond online.

How to read an IRS letter and find the reason

IRS letters follow a standard format. At the top is your name, address, and a notice number (usually starting with CP, as in CP2000 or CP05). Below that is the date the letter was sent. The first full paragraph or section states the reason — for example, "We adjusted your return because you reported income that does not match our records" or "We are notifying you that your refund has been issued."

Below the reason, the letter explains what the IRS found or what action they took. If money is involved, there will be a calculation showing how much you owe or how much the IRS is refunding. At the bottom of the letter are instructions: whether you need to respond, the deadline to respond, and how to respond (phone number, mailing address, or website link).

The notice number is important. If you need to call the IRS or write back, having the notice number speeds up the process because it tells the IRS exactly which letter and which issue you are referring to.

Common reasons the IRS sends letters

Income mismatch: The IRS received a W-2, 1099, or other income report from your employer or a financial institution that does not match what you reported on your return. The IRS will ask you to either report the missing income or explain why the amounts differ.

Missing or incomplete information: You did not include a required document (such as a Schedule C for self-employment income), or a form was incomplete. The IRS will ask you to send the missing information or file an amended return.

Math or clerical error: The IRS found an arithmetic mistake on your return. They will correct it and tell you the new amount you owe or the new refund amount.

Refund status: The IRS is notifying you that your refund has been processed, issued, or delayed. These letters are informational and usually do not require a response.

Balance due: You owe taxes from a prior year or the current year. The letter will state the amount, the deadline to pay, and payment options.

Audit notice: The IRS is selecting your return for examination and asking you to provide documents to support items on your return. These letters include a deadline and instructions for submitting documents or requesting a meeting.

What to do if you receive an IRS letter

First, read the entire letter and locate the notice number and deadline. If the letter asks for a response, the deadline is usually 30 days from the date on the letter. Do not ignore the deadline — the IRS will continue collection action or deny your position if you do not respond.

If the letter asks for documents or information, gather what you have and send it by the deadline. Use the address or online portal listed in the letter. If you are sending documents by mail, include a copy of the letter or the notice number so the IRS knows which account and which issue your response relates to.

If you do not have the documents the IRS is asking for, send a written explanation of why you cannot provide them and what you can provide instead. The IRS may accept partial information or allow you to request an extension.

If you disagree with what the IRS says in the letter, you have the right to respond and explain your position. The letter will include instructions for requesting a conference or submitting a written response. You do not have to agree with the IRS information to respond — the point of responding is to present your side of the issue.

How to contact the IRS about your letter

Every IRS letter includes a phone number you can call to ask questions. This is the fastest way to get clarification if you do not understand the letter or need an extension. Have the letter in front of you when you call, and be ready to provide your Social Security number or tax ID.

You can also respond by mail. Write a letter explaining your response or enclosing the documents the IRS requested. Include your name, address, Social Security number, the notice number from the IRS letter, and the tax year in question. Mail it to the address shown in the IRS letter.

Some IRS letters include a link to an online tool where you can respond directly through the IRS website. If your letter mentions this option, it is usually the fastest way to respond because the IRS receives it immediately and can process it without delay.

What happens after you respond to an IRS letter

If you send documents or information, the IRS will review what you sent and send you another letter with their decision. This usually takes 30 to 60 days, depending on how busy the IRS office is and how complex your issue is. If the IRS needs more information, they will send you another letter asking for it.

If you owe money and the letter is a balance due notice, you can pay immediately or set up a payment plan. The letter will include payment options: online through IRS.gov, by phone, by mail, or through an installment agreement. Paying or setting up a plan stops penalty and interest from continuing to grow.

If you disagree with the IRS decision after they respond, you have the right to appeal. The letter will include information about how to request an appeal or how to file a claim in Tax Court. These are formal processes, and many people consult a tax professional at this stage.

Red flags: Scams that look like IRS letters

Scammers send fake IRS letters to trick people into sending money or personal information. Real IRS letters come by mail, not email or text. The IRS will never threaten you with immediate arrest or demand payment by gift card, wire transfer, or cryptocurrency.

If you receive an IRS letter by email or text, it is a scam. Delete it. If you receive a paper letter that seems suspicious — for example, it demands immediate payment or threatens legal action without giving you a chance to respond — call the IRS directly using the phone number on the official IRS website (IRS.gov) to verify whether the letter is real.

Real IRS letters give you time to respond, explain what you owe or what they found, and include a notice number and contact information. If a letter does not have these things, it is likely fraudulent.

Frequently Asked Questions

What if I lost the IRS letter and do not know what notice number it was?

You can check your IRS account online at IRS.gov using your login credentials. Your account will show all notices and letters the IRS has sent you, including the notice number and the reason. You can also call the IRS using the phone number on your most recent tax return or a prior IRS letter.

Do I have to respond to every IRS letter?

No. Some letters are informational only — for example, a letter confirming your refund was issued. These letters do not require a response. However, if the letter asks you to provide information, send documents, or respond by a certain date, you must respond by that deadline or the IRS will take further action.

What if I cannot meet the deadline to respond?

Call the IRS phone number on the letter and ask for an extension. The IRS will usually grant a 30-day extension if you ask before the deadline. Explain why you need more time and what you are working on. Getting an extension in writing protects you if the IRS later claims you did not respond on time.

Can I ignore an IRS letter if I think it is wrong?

No. Ignoring the letter does not make the issue go away. The IRS will continue collection action, add penalties and interest, or pursue enforcement. The correct step is to respond by the deadline, explain why you disagree, and provide any documents that support your position. If you still disagree after the IRS responds, you can request an appeal.

What if the IRS letter says I owe money but I already paid?

Call the IRS using the phone number on the letter and explain that you paid. Have your payment confirmation or bank statement showing the payment. The IRS will research your account and send you a corrected letter. Do not ignore the original letter — contact the IRS to resolve it quickly.