IRS CP23: what it means and what to do

• The estimated tax payments on your return didn't match what the IRS posted to your account
• The notice may also include other adjustments made while processing your return

1. Compare the payments on the notice with your records, including all estimated payments and any prior-year payments applied
2. If you agree, pay the balance by the date on the notice
3. If you can't pay in full, set up a payment plan
4. Correct your own copy of the return but don't send it to the IRS
5. If you disagree, contact the IRS at the number on the notice by the date indicated

Deadline: Pay by the date shown on your notice to avoid additional penalties and interest; contact the IRS by the date indicated if you disagree

Call the number on the notice by the date indicated. Free help is available from the Taxpayer Advocate Service and Low Income Taxpayer Clinics.

If you don't pay in full, you will usually receive a late payment penalty, and interest continues until the account is fully paid.

Most notices come down to matching what the IRS has on file against your own records. Before you reply, pull the return the notice refers to, the bank statements and income forms for that year, and any payment confirmations. If your books are reconciled to the bank, that comparison takes minutes instead of days.

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IRS: Understanding your CP23 notice →

Last verified against that page on October 13, 2026. This is general information, not advice for your situation. The notice itself is the authority on your amounts and dates. Talk to a CPA or enrolled agent if the amounts are large or you are unsure.

• All IRS notices explained
• IRS CP2000 — The IRS is proposing changes to your tax return because income or payment information it received from third parties does not match what you reported.
• IRS CP14 — The IRS says you owe money on unpaid taxes.
• IRS CP501 — This is a reminder that you still owe a balance on one of your tax accounts.
• IRS CP503 — This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices.
• IRS CP504 — This is a Notice of Intent to Levy under Internal Revenue Code section 6331(d) and a final reminder that the IRS may levy your wages, bank accounts, or state tax refund for an unpaid balance.
• IRS LT11 — The IRS has not received payment for overdue taxes and intends to seize your property or rights to property.
• Find an accountant — for help responding.