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In the IRS’s own words · not reviewed by VALID

CP23 notice explained, in the IRS’s own words

We corrected your return because we found a difference between the amount of estimated tax payments on your tax return and the amount we posted to your account. You have a balance due because of these changes. The notice may also cover other changes we made while processing your return.

Read the full CP23 page on irs.gov ↗

Quoted from www.irs.gov/individuals/understanding-your-cp23-notice, read October 15, 2026 · fingerprint 0b6f9dbb5711 · 1 line left out here (see irs.gov)

What this notice is about

We corrected your return because we found a difference between the amount of estimated tax payments on your tax return and the amount we posted to your account. You have a balance due because of these changes. The notice may also cover other changes we made while processing your return.

What you need to do

Read your notice carefully to see what was changed on your return and how those changes affected your balance. Compare the payments on the notice to your records:

  • Verify we listed all your estimated tax payments.
  • Check the payments we applied (if any) from the prior year.

If you agree with the changes we made

  • Pay the amount owed by the date shown on your notice to avoid additional penalties and interest.
  • Make arrangements to pay over time if you can't pay the full amount right now.
  • Correct the copy of your tax return that you kept for your records, but do not send it to us.

If you disagree with the changes we made

Contact us at the number shown on the notice by the date indicated.

You may want to

Visit Online Account to:

  • Access tax records
  • View your balance
  • Make and view payments
  • View or create payment plans
  • Manage your profile preferences
  • View tax professional authorizations
  • Learn more about accessibility options
  • View tax transcripts

I don’t pay estimated taxes. Why did I get this notice?

The most common cause is an incorrect entry on the estimated tax line of the tax return. If this happened, call the number in the "Where to find more information" section of your notice.

How can I find out what caused my tax return to change?

Review the "What we changed on your return" section of your notice. For more information about the errors on your return, call us at the number shown in "Where to find more information."

What should I do if I find you misapplied a payment or haven't credited a payment that I made?

Call us at the number in the "Where to find more information" section of your notice. Have a copy of your tax return and documentation (such as cancelled checks or amended return) ready when you call. We'll discuss the issue with you and give you further instructions.

What is an estimated tax penalty?

We may assess an estimated tax penalty if you didn’t pay enough tax throughout the year, either through withholding or by making estimated tax payments. See our Estimated taxes page, or Tax Topic 306, Penalty for underpayment of estimated tax.

How do I adjust my estimated tax payments?

Complete a Form 1040-ES, Estimated Tax for Individuals PDF. See Publication 505, Tax Withholding and Estimated Tax PDF for more information.

Do I receive a penalty if I cannot pay the full amount?

Yes. You will usually receive a late payment penalty. If we adjust your account (such as fixing a misapplied payment), the late payment penalty and interest will adjust automatically. For additional help, see Penalty relief.

Do I have to pay interest on the amount I owe?

To avoid interest charges, pay the amount owed by the due date on the payment coupon. We can't reduce interest for reasonable cause or first-time relief. We're required by law to charge interest, and it will continue until your account is fully paid. However, if we reduce your tax or penalty, the interest will automatically be reduced.

What should I do if I need to make another correction to my tax return?

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

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.

To help avoid the same issue next year, correct the copy of this year’s tax return that you kept for your records. If you use a tax preparer, also have them correct their copy.

Before filing your return, you can verify the estimated tax payments were applied to the year by viewing your tax account.

What to do next

  • Write down the date on the letter today.
  • Look the number up on irs.gov yourself. Don’t trust a link or phone number from anyone else.
  • If it says you owe money or proposes changes to your return, take it to a licensed CPA, EA or tax attorney before that date.

Not advice. Not a filing. Verify with a licensed professional. Rules change by year and facts.

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