IRS CP23 Notice: Estimated Payments Don't Match — Balance Due

What the IRS says: “The estimated tax payments claimed on your return don't match IRS records, leaving a balance due.” Here’s what it actually means, your deadline, and exactly how to respond.

Return AdjustmentsTime-sensitiveDeadline: 21 daysFree response letter draft

What CP23 actually means

One of the most disputable notices the IRS sends: its estimated-payment ledger and yours disagree. Payments applied to the wrong year, spouse-vs-primary SSN application, and fourth-quarter payments recorded in the wrong tax year cause a large share of CP23s — and all of those are your win with bank proof.

Notice family: Return Adjustments — The IRS changed something on your return — math corrections, credit adjustments, payment mismatches. Often correct, frequently not. You typically have 60 days to dispute a change you disagree with.

Your deadline

21 days — pay-by date — but respond with proof instead if the IRS's ledger is wrong.

Counted in calendar days from the notice date. The exact respond-by date printed on your notice always controls — check page 1.

Why you received CP23

What to do about CP23

1

Step 1

Pull every estimated-payment confirmation and bank record for the year

2

Step 2

Match them against the notice's payment list — find the missing/misapplied one

3

Step 3

Respond with proof (canceled checks, EFTPS/Direct Pay confirmations, both spouses' SSNs noted)

4

Step 4

If your claim was wrong: pay, and fix the estimated-payment tracking that caused it

How to respond

A payment-trace letter listing each payment (date, amount, confirmation number, which SSN) with proof attached gets misapplied payments moved and the balance recomputed. This notice family has one of the highest taxpayer-win rates.

Draft a CP23 response letter now ↓

Draft your response letter

Describe the notice and your side of it — use placeholders, never your SSN or account numbers (the letter keeps [YOUR NAME]-style fields so you fill in the real details privately before mailing). A mail-ready draft with an enclosure checklist comes back in ~20 seconds.

Your IRS response letter draft will appear here.

Frequently asked questions

What does IRS CP23 mean?

The estimated tax payments claimed on your return don't match IRS records, leaving a balance due. In practice: One of the most disputable notices the IRS sends: its estimated-payment ledger and yours disagree. Payments applied to the wrong year, spouse-vs-primary SSN application, and fourth-quarter payments recorded in the wrong tax year cause a large share of CP23s — and all of those are your win with bank proof.

How long do I have to respond to CP23?

You generally have 21 days — pay-by date — but respond with proof instead if the IRS's ledger is wrong. The respond-by date printed on your own notice always controls.

Should I respond to CP23 in writing?

A payment-trace letter listing each payment (date, amount, confirmation number, which SSN) with proof attached gets misapplied payments moved and the balance recomputed. This notice family has one of the highest taxpayer-win rates.

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