IRS Letter 2645C: What It Means and What to Do Next

IRS Letter 2645C is an interim letter. It means the IRS received something from you — a reply to an earlier notice, an amended return, identity verification documents, or a submission from your representative — and needs more time before it can give you an answer. It is not a bill, it is not a notice of audit, and it does not say you did anything wrong.

In most cases there is nothing to send back. The letter exists because the IRS owes you contact within a set window and does not yet have a decision to give you. What matters is knowing what the letter is required to tell you, how long the IRS is allowed to take, and when a delay stops being routine and starts being a problem worth acting on.

What IRS Letter 2645C actually is

The IRS works to an internal deadline when correspondence arrives. Under Internal Revenue Manual 21.3.3, “a final response or interim letter initiated within 30 days of the IRS received date is considered a timely response.” When the IRS cannot finish the work inside that window, it does not simply go quiet. The manual states that “an interim letter is required to be sent within 30 days of the received date if a final response cannot be issued.”

Letter 2645C is that interim letter. It is an acknowledgment generated because the IRS has an obligation to contact you and does not yet have an answer. Read that way, the letter is actually useful information: it confirms your submission landed and is in the queue.

What Letter 2645C does not mean

• It is not a notice that your return has been selected for examination.
• It is not a bill. If you have a balance, that is tracked separately and will have its own notice.
• It is not a denial of whatever you asked for. No decision has been made yet.
• It is not a sign your paperwork was lost. The opposite — it is the IRS confirming receipt.

Why you received a 2645C letter from the IRS

An interim letter follows something the IRS received. The most common triggers are:

• You replied to an earlier IRS notice, with or without documentation.
• You filed an amended return.
• You sent identity verification documents.
• You requested penalty relief.
• Your representative filed an authorization and asked the IRS to act on your account.
• You responded to an examination or underreporter notice.

You do not have to guess which one applies. The manual requires the IRS to “identify the reason a final response is delayed” in the letter itself. If the reason printed on your letter does not match anything you sent, that mismatch is worth looking into rather than filing away.

Do you need to respond to IRS Letter 2645C?

Usually, no. The IRS’s general guidance on notices and letters is direct: “You don’t need to reply unless we specifically ask you to.” An interim letter is, by design, the IRS reporting on its own progress rather than asking you for something.

That said, read your copy before you decide. If the letter does ask for a document, a signature, or a clarification, that request carries its own due date, and the IRS is explicit that “to guarantee your appeal rights, reply by the due date.” Treat any dated request on the page as the real deadline and work backward from it.

Either way, keep the letter. IRS guidance on any notice is to “review it carefully and keep it for your records.” The contact details printed on it are the fastest route back into your own case file later.

What the letter is required to tell you

Interim letters are not meant to be vague. IRM 21.3.3 sets out what has to be on the page:

• The reason the final response is delayed.
• When the final response will be mailed — the manual instructs staff to “include in all interim letters when a taxpayer can expect a final resolution.”
• “The name, telephone number, and unique employee identification number of a contact person.”

There is no single universal waiting period that applies to every 2645C letter. The date on your letter is the date that governs your case, and it is the one to put in your calendar. If your copy is missing the reason, the date, or the contact information, that is a defect in the letter and a fair reason to call the number shown and ask for the missing piece.

Letter 2645C vs. Letter 2644C

These two letters are often confused because they look similar and say similar things. The difference is sequence. Letter 2645C is the first interim response. Letter 2644C is the second one, sent when the IRS misses the date it gave you the first time. The manual puts it this way: “subsequent interim letters, for example, the 2644C Letter, Second Interim Response, must be issued if a final resolution cannot be provided by the promised date included in the initial interim letter.”

One 2644C after a 2645C is not unusual. A run of them is a signal that the case is not moving, and it changes what you should do next.

What to do while you wait

Diary the date and keep the file together

Put the date from the letter on your calendar and keep a single folder with what you sent, when you sent it, proof of delivery, and every letter back. If the case stalls, that file is what makes the next conversation short.

Check your IRS account rather than waiting blind

An IRS Online Account lets you “view balances owed to the IRS by tax year,” “view up to 5 years of payment history,” “view digital notices from the IRS,” and “view key tax return information, including your adjusted gross income, and access transcripts or tax compliance report.” Account activity often shows movement before a letter arrives in the mail.

If you owe, interest does not pause

This is the part people miss. An interim letter says nothing about your balance. The IRS charges interest on underpayments “starting on the due date of the amount you owe,” and it “will continue to accrue until the balance is paid in full.” The IRS also notes that paying even part of what is owed by the due date can “reduce interest and penalty charges.” Waiting on a review and paying down a balance are two separate decisions.

When the delay stops being routine

A single interim letter is ordinary. These situations are not:

• The date on the letter has passed with no final response and no second interim letter.
• You have received several 2644C letters in a row.
• The reason given for the delay does not match what you actually sent.
• Collection activity continues on the same tax year the correspondence was meant to resolve.
• The delay is creating a hardship you cannot absorb.

The Taxpayer Advocate Service is “an independent organization within the IRS, that helps taxpayers solve problems with the IRS and recommends changes to prevent them,” and unresolved problems and notices are among the issues it handles. A licensed representative can also pull your transcripts, confirm what the IRS actually has on file, and press the case through the contact listed on the letter.

Frequently asked questions

What is an IRS 2645C letter?

It is an interim letter. The IRS sends it to acknowledge correspondence it received and to tell you it needs more time before it can issue a final response.

Why did I get a 2645C letter from the IRS?

Because something you or your representative sent is still being worked. IRM 21.3.3 requires an interim letter within 30 days of the IRS received date when a final response cannot be issued in that window.

Do I have to respond to IRS Letter 2645C?

Generally not. IRS guidance on notices is that “you don’t need to reply unless we specifically ask you to.” Read your letter — if it does request something, that request has its own due date.

Does Letter 2645C mean I am being audited?

No. It is a processing acknowledgment, not an examination notice. An audit is opened by its own letter, which says so plainly.

What is the difference between Letter 2645C and Letter 2644C?

2645C is the first interim response. 2644C is the second, issued when the IRS cannot resolve the matter by the date it promised in the first letter.

How long will the IRS take after sending Letter 2645C?

There is no fixed period that applies to every case. The IRS is required to state in the letter when you can expect a final resolution, so the date printed on your copy is the one that applies to you.

Can I call the IRS about Letter 2645C?

Yes. Interim letters are required to carry “the name, telephone number, and unique employee identification number of a contact person.” If you suspect a letter is not genuine, the IRS directs taxpayers to call 800-829-1040 rather than the number on the document.

The short version

IRS Letter 2645C means your submission was received and the answer is still coming. Read it for the reason and the date, keep it with the rest of your file, watch your account, and keep paying attention to any balance that is accruing interest in the background. If the date passes and nothing happens, or the letters keep repeating, that is the point to get a representative involved rather than wait another cycle.