The Federal Tax Desk

CP24: The Refund Notice That Says No Response Is Required

By Forrest Baumhover, CFP®, EA · Last verified August 17, 2026

A CP24 says the IRS recalculated your estimated tax payments and found money in your favor. It is the notice practitioners are least likely to read closely and the one most likely to be reporting a payment that posted somewhere it should not have.

What the notice actually says

A CP24 opens with a single sentence that does all the work: "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." The correction ran in the taxpayer's favor. The account now shows an overpayment, and the notice tells the client to expect a refund. (For how CP24 fits among the other IRS notices, see the IRS Notice Library.)

The internal name for the notice is more precise than the letter itself. The IRS catalogues it as "Estimated Tax Credits Discrepancy — We Changed Your Return to Match Your Credits or Payments Posted to Your Account — You May Have a Credit or Overpayment." Read that title and the notice stops being about a refund. It is about the IRS resolving a disagreement between two records of the same payments, and then telling you which record won.

The line clients actually read is "no response is required." That line is accurate. It is also why this notice gets filed unread more often than any other in the library. A refund the client was not expecting is welcome news, and welcome news does not get audited. But the refund can be correct while the reason for it is wrong, and the reason is what decides whether the money is the client's to keep.

What actually triggered it

A CP24 issues when the estimated tax credits claimed on the return and the credits posted to the account disagree, and the recomputation produces an overpayment of $1.00 or more. That dollar is the entire difference between this notice and its siblings. IRM 21.3.1.6.17 defines this notice; the same discrepancy resolved into a balance due of $1.00 or more is IRM 21.3.1.6.16's CP23, and a near-even result is IRM 21.3.1.6.18's CP25 — though CP25's own threshold is not symmetric: an overpayment under $1.00, or a balance due under $5.00. One determination, three notices, split by arithmetic.

The causes underneath are ordinary. The Taxpayer Advocate Service lists them plainly: a payment the taxpayer reported that never posted, a payment applied to the wrong year or the wrong taxpayer, or a claimed figure that simply does not match the IRS's record. To that list add the prior-year carryforward — the overpayment a client elected on last year's return to apply against this year's estimated tax. That one is the most common single source of a mismatch, because it is the only figure on the return that requires two different tax years to agree about one number.

One trigger never appears on the taxpayer-facing page. The IRM notes that beyond the estimated tax discrepancy, "a CP 24 may advise the taxpayer their return contained a math error or the statute for refund has expired." So a CP24 can carry a second, unrelated adjustment, and it can report an overpayment the IRS has already decided it will not pay out, because IRC §6511's refund limitations period closed first. The notice's headline announces neither one.

Response deadline and what happens if you miss it

The plain CP24 tells a disagreeing taxpayer to call "by the date indicated" and prints a date rather than a rule. The rule is 60 days from the notice date. TAS states it directly, and the IRS states it in so many words on the CP24G and CP24U variants: contact within 60 days of the notice date and supply supporting documentation. A phone call can settle a straightforward posting question during the call. A written response takes 90 days or more, so the choice of channel is a real one when the deadline is close.

What that 60 days is depends on which adjustment you are answering. For the estimated tax credit discrepancy itself, it is an administrative window. Missing it forfeits no statutory right — the client can still amend, and can still file a refund claim inside the §6511 period. For a math error riding along on the same notice, the 60 days is statutory: IRC §6213(b)(2)(A) requires the IRS to abate that assessment on request made within 60 days, and the request does not have to be persuasive, only timely. One notice, two clocks, and only one of them costs a right when it runs out.

If the notice is right and nobody disputes it, the IRS expects to release the refund within four to six weeks — "provided you don't owe other taxes or debts we're required to collect." That condition is IRC §6402, which lets the Service apply an overpayment against any internal revenue tax liability first and requires it to offset past-due child support, federal agency debt, and state income tax before refunding a balance. And if the IRS holds no working deposit route for the account, the refund generates a second notice of its own — a CP53E asking for banking details.

The practitioner's actual next step

Reconcile against the transcript, not against the client's records. The client's records are what produced the disagreement. Pull the account transcript through The Federal Tax Desk's IRS Transcript Analyzer and match every estimated payment the return claimed against what actually posted, by date and by amount. Where a payment moved between periods or between taxpayers, a transaction code records the move; the Transcript Decoder will tell you which one you are looking at and what it means. This is a twenty-minute exercise that answers the only question the notice leaves open.

Check the carryforward election specifically. IRC §6513(d) makes it a one-way door: once an overpayment is credited against the succeeding year's estimated tax, that amount "shall be considered as a payment of the income tax for the succeeding taxable year," and "no claim for credit or refund of such overpayment shall be allowed for the taxable year in which the overpayment arises." If a CP24 refunded money the client elected to carry forward, the current year's first estimated payment just left the account and nobody has told the client. Rebuild the remaining estimates before the next due date, not after the underpayment penalty computes.

Then ask the question the refund discourages: is this credit actually the client's? A payment posted to the wrong period, the wrong spouse's account, or a similar taxpayer identification number produces a real overpayment on the wrong account. Accepting that refund settles nothing. The IRS reverses the credit when it finds the error, the balance returns with interest running from the original due date, and it arrives as a CP14 that the client will read as coming out of nowhere. A CP24 the client cannot explain is worth resolving before the money is spent.

What CP24 gets confused with — and why the distinction matters

The notice CP24 is genuinely confused with is CP23, and the confusion is understandable, because the IRS opens both with the same sentence word for word. CP23 reports the identical estimated tax credit discrepancy resolved into a balance due instead of an overpayment. Same determination, same investigation, opposite sign. The practical consequence is one-directional: a CP23 client investigates, because they now owe money, while a CP24 client rarely does, because they do not. The underlying posting defect is the same in both cases, and only one of the two gets caught.

The distinction practitioners get backwards is the abatement right. Because the IRS assesses these adjustments the way it assesses math errors, the natural inference is that the math-error abatement right travels with them. It does not. IRC §6201(a)(3) lets the Secretary assess an overstated estimated tax credit "in the same manner as in the case of a mathematical or clerical error appearing upon the return, except that the provisions of section 6213(b)(2) (relating to abatement of mathematical or clerical error assessments) shall not apply with regard to any assessment under this paragraph." The carve-out is explicit. It bites hardest on the CP23 side, and it is exactly what a CP24 client faces if the IRS later reverses the credit it just granted.

Two further notices get mistaken for this one and are worth separating cleanly. CP12 says "We corrected one or more mistakes on your tax return" — any mistake, not specifically an estimated tax one — so a CP12 refund tells you nothing about where a payment posted, which is the whole content of a CP24. CP49 says the IRS "used all or part of your refund to pay a tax debt," and it is usually the answer when a CP24 promised four to six weeks and nothing arrived. The CP24E, CP24G, and CP24U variants are not separate problems: they carry the same determination through a different issuing path, and the IRS covers them with the same guidance it gives for CP24.

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