CP23: estimated payments didn't match, and you owe

What a CP23 means

A CP23 means the IRS corrected your return because the estimated tax payments you listed didn't match the payments posted to your account, and that left a balance due. The notice may include other changes too. [1]source 1

Under federal law, a math or clerical error notice isn't a notice of deficiency. The IRS can assess the corrected tax right away, and you can ask it to abate that assessment within a set period after the notice. If you ask in time, the IRS must abate it, and any reassessment has to go through the normal deficiency process. [2]source 2

Most CP23s come down to one question: where did a payment go? Answer that and the rest usually follows.

Why people get one

• An estimated payment was applied to a different year or a spouse's account.
• A wrong figure was entered on the estimated tax line of the return. [1]source 1
• A prior-year overpayment was smaller than you expected.

First steps

1. List every estimated payment you made for that year, with dates and confirmation records, and compare it with the notice. [1]source 1
2. Check your IRS online account, typed in yourself at irs.gov, to see the notice and your balance or payments.
3. If a payment is missing or misapplied, call the number printed on your notice with your return and records, such as canceled checks. [1]source 1
4. If you agree, pay by the date on the notice or set up a payment plan. [1]source 1
5. Before you file next year, check your account to confirm the estimated payments landed in the right year. [1]source 1

What not to do

• Don't pay twice. Find the missing payment first.
• Don't pay or send documents through a link or phone number in an unexpected email or text. Use irs.gov, typed in yourself.
• Don't ask for interest relief on reasonable-cause grounds. The IRS says it can't reduce interest that way, though interest falls if the tax or penalty falls. [1]source 1

Related notices

• Related CP24 The same kind of mismatch, but it leaves you a credit instead of a balance.
• Related CP11 A correction that leaves a balance due.
• Related CP12 A correction that changes a refund or creates one.

Keep reading

• Estimated tax
• Section 6213

Questions