Notice code CP21B
You got a CP21B. A refund is on the way.
You are holding a CP21B, which means the IRS made the changes you asked for on your return.
The IRS says your refund arrives 2 to 3 weeks after the notice, and you owe no reply.
First check that the notice is real, then compare its amounts with your own copy of the return.
Briefing for CP21B
IRS pageThe IRS changed your return the way you asked and is sending you a refund.
No reply is needed.
- Do nothing and wait for your refund to arrive.
- Call the number on the notice if something looks wrong.
- File Form 1040-X if you need another correction.
Which numbers matter?
2 to 3 weeks
Your refund should land 2 to 3 weeks after the notice, unless the IRS uses it to pay other taxes or debts.
Call the number on the notice if 3 weeks pass with no refund.
$10
If the IRS paid you $10 or more in interest, you get a Form 1099-INT for it.
Report that interest as income on next year's return.
January 31
Your Form 1099-INT for the refund interest arrives by January 31 of next year.
Watch for the form and keep it with your tax papers for next year.
What changed recently?
Since September 30, 2025, the IRS has stopped sending paper refund checks to individual taxpayers, with limited exceptions. Your CP21B refund goes out electronically, mainly by direct deposit.
Source: Questions and answers about Executive Order 14247 (paper refund checks).
What is the IRS saying?
This is good news. The notice shows the corrected amounts and the refund, which can include interest the IRS paid you.
Why did you get it?
You or your preparer sent a correction, often a Form 1040-X. Take Florian. He amended his 2024 return to add a missed education credit.
Is it real?
The notice has a section headed "What you need to know" with the number to call. No payment is asked for.
Still unsure? Search the code on the IRS notice search, or use the real or fake checklist.
When is your deadline?
No reply is needed. If 3 weeks pass with no refund, and you owe no other debts the IRS must collect, call the number on the notice.
What if you agree?
Correct your own copy of the return and report any interest on next year's return. If you get $10 or more in interest, a Form 1099-INT arrives by January 31.
What if you don't agree?
Call the number on the notice. If you need another correction, file Form 1040-X.
What happens if you ignore it?
Nothing bad happens if you agree. Report the interest next year.
What should you read next?
Questions people ask
When will my CP21B refund arrive?
Within 2 to 3 weeks of the notice, the IRS says, unless you owe other taxes or debts such as child support.
Do I pay tax on the interest in a CP21B refund?
Yes, you report it. A Form 1099-INT comes if the interest is $10 or more.
I never asked for a change. Why did I get a CP21B?
Call the number on the notice. If you think someone filed in your name, our identity verification page has the steps.
Who helps if calls do not fix it?
The Taxpayer Advocate Service at 877-777-4778.
Sources
- Understanding your CP21B notice. Published by irs.gov.
- Questions and answers about Executive Order 14247 (paper refund checks). Published by irs.gov.
Last checked October 2026
What to do now
- If the notice looks suspicious, call the IRS at 800-829-1040 to confirm it is real.
- Compare the corrected amounts with your copy of the return and update your own records.
- Call the number on the notice if 3 weeks pass with no refund.
- Report any refund interest on next year's return using your Form 1099-INT.
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.