Information For...

For you and your family
Standard mileage and other information

Forms and Instructions

Individual Tax Return
Instructions for Form 1040
Request for Taxpayer Identification Number (TIN) and Certification
Request for Transcript of Tax Return


Employee's Withholding Allowance Certificate
Employer's Quarterly Federal Tax Return
Employers engaged in a trade or business who pay compensation
Installment Agreement Request

Popular For Tax Pros

Amend/Fix Return
Apply for Power of Attorney
Apply for an ITIN
Rules Governing Practice before IRS

Understanding your CP21A Notice

We made the changes you requested to your tax return for the tax year on the notice. You owe as a result of the changes.

What you need to do

  • Read your notice carefully. It will explain why you owe.
  • Contact us is you disagree with the changes we made.
  • If you agree with our changes, correct the copy of your tax return that you kept for your records.
  • Pay the amount you owe by the due date on the notice's payment coupon.
  • Make payment arrangements if you can't pay the full amount you owe.

Answers to common questions

The notice says, "Based on the information you provided, we changed your 20XX Form 1040 to correct your:...," but I don't remember sending any change to IRS. How can I find out what you received to make this change?

Call us at the toll-free number listed on the top right corner of your notice.

What do I say when I call the IRS?

Mention that you received a CP21A notice with a balance due and you need to review your account. Be sure to have a copy of your notice and your tax return before you call.

What should I do if I disagree with the changes you made?

Call us at the toll-free number listed on the top right corner of your notice.

What happens if I can't pay the full amount I owe?

You can arrange to make a payment plan with us.

Am I charged interest on the money I owe?

Yes, interest will accrue if you don't pay the full amount you owe by the date on the payment coupon.

Will I receive a penalty if I can't pay the full amount?

Yes, you'll receive a late payment penalty. You can call us at the number listed on your notice if you’re unable to pay the full amount shown because of circumstances beyond your control. If you contact us by the due date of your payment, we may be able to remove the penalty, depending on your situation.

What if I need to make another correction to my account?

You'll need to file Form 1040X, Amended U.S. Individual Income Tax Return.

What if I haven't been able to get answers after contacting IRS several times?

Call our Taxpayer Advocate at 877-777-4778 or for TTY/TDD 800-829-4059.

What if I think I’m a victim of identity theft?

Call us at the number listed on the top right corner of your notice. See the IRS Identity Theft resource page for more information.

Tips for next year

Consider filing your taxes electronically. Filing online can help you avoid mistakes and find credits and deductions that you may qualify for. In many cases you can file for free. Learn more about e-file.

Printable samples of this notice (PDF)

How to get help