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IRS notice decoder · Corrections the IRS made

CP13: the IRS corrected your return and you owe nothing

A CP13 says the IRS fixed a mistake on your return and your balance is now zero: no refund, nothing owed. Disagree by the date on it.

By the Carry Forward Learning team Reviewed by Hunter Nottingham, JD, CPA

No dated figures Checked Review by

CheckedOct 19, 2026

What a CP13 means

A CP13 means the IRS corrected one or more mistakes on your return, and after the changes you aren't due a refund and don't owe more. The balance is zero. 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. source 2

Zero sounds like the end of it, and often it is. But if you expected a refund, the change cost you something, and it's worth checking.

The date that counts

If you disagree, contact the IRS at the number on the notice by the date shown on it. If you don't contact the IRS by the date on the notice, the IRS says you lose formal rights to have the changes reversed and your right to appeal to the Tax Court. Documents sent later are still considered, and the IRS may reverse the change if it agrees. source 1

Why people get one

  • You expected a refund, and a correction took it to zero.
  • You expected to owe, and a correction took it to zero.
  • An arithmetic or transfer error was fixed.

First steps

  1. Read the part of the notice that lists what changed and find that line on your return. 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 you agree, you don't need to respond. Correct your own copy, but don't send it to the IRS. source 1
  4. If you disagree, call the number printed on your notice by the date shown, with your return and documents in front of you. source 1
  5. If you need to make a different correction, the IRS points to Form 1040-X. source 1

What not to do

  • Don't treat zero as proof the return was right. Check the change.
  • 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 let the date pass if you disagree. source 1
  • Related CP11 A correction that leaves a balance due.
  • Related CP12 A correction that changes a refund or creates one.
  • Related CP10 A correction that changes the estimated tax carried to next year.

Keep reading

Questions

Do I need to respond to a CP13?

Not if you agree. If you disagree, contact the IRS by the date on the notice. source 1

What if I send documents after the CP13 date?

The IRS says it will still consider them and may reverse the changes if it agrees, but the formal right to a reversal and to the Tax Court is gone. source 1

Sources

  1. IRS, Understanding your CP13 notice (updated August 11, 2026) (external site) checked Oct 19, 2026
  2. 26 U.S.C. section 6213 (deficiency procedures; math and clerical errors) (external site) checked Oct 19, 2026

Every rule on this page comes from the IRS page in the list, read on the date shown. Your notice itself is the final word on its own dates and amounts.