CP23
informationalEstimated Tax Credits Discrepancy — Balance Due
You claimed more in estimated tax payments than the IRS has on record, and now you owe.
No day count is published. Pay by the date shown on the notice.
If it passes. Additional penalties and interest.
Why you got it
A difference between the estimated payments on your return and the payments posted to your account.
What rights it carries
Publication 5 appeal rights. The page does not mention Tax Court or a 60-day window.
Do you have to respond?
Response required only if you disagree. Payment is required either way.
The mistake people make
Assuming the IRS has the payment record right. These are frequently posting errors — a payment credited to the wrong year, the wrong spouse's number on a joint account, a payment applied to an older balance. Pull the account transcript before you pay.
If crypto is why this arrived, the number on it is probably wrong.
Your exchange reports what you sold for and leaves the cost box blank, so any figure the IRS computes from it treats every coin as though it cost you nothing. Rebuild the basis from your own transaction history — free — and see the real number before the deadline above runs out.
Notices that arrive around this one
CP3219A — The formal determination that you owe more tax — the ninety-day letter, and your one ticket to Tax Court without paying first. CP11 — The IRS corrected something on your return and now says you owe money. CP12 — The IRS corrected your return and you are owed a refund, or your refund amount changed. CP14 — Your first bill. Tax has been assessed and it has not been paid.Every notice in the library → Not sure it is really from the IRS? →
Sources: IRS — Understanding your CP23 notice. Retrieved 2026-08-28. Where the IRS publishes no day count we say so rather than repeat a number we cannot source — the date printed on your own notice is the one that governs. ClearBasis is tax software, not a tax adviser, and this is information rather than advice.