Notice code Letter 2645C
You got Letter 2645C. Your case is still open.
You are holding IRS Letter 2645C, and your case is still open.
It is an interim letter, so the IRS needs more time and sets no new deadline unless the letter names one.
Read it for any request, then check that it is real before you act.
Briefing for Letter 2645C
IRS pageAn interim letter saying the IRS has your case and needs more time to answer.
No new deadline unless the letter names one.
- Wait and keep copies of what you sent.
- Send anything the letter asks for.
- Call the number on the letter if the wait runs long.
Which numbers matter?
800-829-1040
This is the IRS line to call if the letter looks wrong or fails your search.
Search the letter number on the IRS notice page before you call.
877-777-4778
The Taxpayer Advocate Service can step in when your case stalls past the wait the letter gives.
Call it only after the number on your letter has not moved your case.
What is the IRS saying?
The letter usually follows something you sent, such as a reply to a notice or an amended return. It asks for nothing new unless it says so.
Why did you get it?
Take Ray. He answered a CP2000 in July. In September he got Letter 2645C saying the IRS needed more time to review his papers.
Is it real?
Search the letter number on the IRS notice page. If it does not appear or looks wrong, the IRS says call 800-829-1040.
Still unsure? Search the code on the IRS notice search, or use the real or fake checklist.
When is your deadline?
No new deadline unless the letter names one. Earlier deadlines from your original notice still count.
What if you agree?
Wait, and keep copies of what you sent.
What if you don't agree?
If the wait runs past the time the letter gives, call the number on it. The Taxpayer Advocate Service at 877-777-4778 helps when normal channels stall.
What happens if you ignore it?
Read the letter for any requested action, then keep it with your earlier reply. An interim letter does not erase deadlines on other notices.
What should you read next?
Questions people ask
Does Letter 2645C mean I owe money?
No. It is an interim letter about a case still open.
Do I need to reply to Letter 2645C?
Only if the letter asks for something.
What if I wait longer than the letter says?
Call the number on the letter, then the Taxpayer Advocate Service if it stalls.
How do I know Letter 2645C is real?
Search its number on the IRS notice page or call 800-829-1040.
Sources
- Internal Revenue Manual 25.25.5. Published by irs.gov.
- Understanding your IRS notice or letter. Published by irs.gov.
Last checked October 2026
What to do now
- Read the letter for any request or date it names.
- Search 2645C on the IRS notice page to confirm the letter is real.
- Keep the letter with copies of the reply you sent earlier.
- Meet any deadline from your original notice, since it still counts.
Still not sure the letter is real? Call the IRS at 800-829-1040 and use that number, not one printed on the letter you doubt.