Income mismatch & return changes
An estimated-tax mismatch: the credits the IRS shows for your quarterly estimated payments don't match what your return claimed, and the difference changed your bill or refund.
Handle it
An estimated-tax mismatch: the credits the IRS shows for your quarterly estimated payments don't match what your return claimed, and the difference changed your bill or refund.
Why you got it: A quarterly payment posted late, posted to a spouse's account, posted to the wrong tax year, or simply claimed for the wrong amount.
Not an accusation — this is one of the most mechanical notices in the system, and one of the most often caused by the IRS's own posting errors (a payment applied to the wrong year or under the wrong SSN).
Your first move: List every estimated payment you made (dates, amounts, confirmation numbers or cancelled checks) against the notice's list. The missing one is usually findable — then call with proof.
The clock on this letter: Respond by the date on the notice if you disagree.
The printed date controls for disputes; any balance shown bills on the standard ladder.
Cancelled check, IRS payment confirmation, or bank record with the date and amount.
Then fix next year's estimates so the mismatch doesn't repeat.
Call the number on the notice with the payment proof in hand; follow up in writing.
Nobody needs your bank login to fix a CP23. Verify payments in your online account instead.
The IRS's version of your payments becomes final, and you can pay tax twice — once at the bank, once on the bill.
Where this sits on the ladder: CP14 →
One payment. No subscription. Yours to keep — every notice, every letter, every script.