What it means
Business return math error corrections, refund due
Respond within
The date printed on the notice
When to get help
If the correction removed a credit worth thousands (EITC, child tax credit, education credits) and you believe you qualify, respond in writing within 60 days and consider help.

The first move

Note the date on the notice and the 60-day window. If you disagree, write within it. After 60 days you owe the tax and must pay before you can dispute.

What letters in this family have in common

Math error authority lets the IRS correct arithmetic, a missing form, a credit claimed with a wrong Social Security number, or a figure that contradicts its records, without an examination. The notice tells you what changed. CP11 means you now owe. CP12 means your refund changed. CP13 means no change to the tax. CP21 and CP22 report changes you requested (an amended return) or the IRS made.

The 60-day rule is the important part. If you ask for the change to be reversed within 60 days of the notice, the IRS must reverse it and, if it still disagrees, go through normal deficiency procedures, which preserves your right to Tax Court before paying. Let the 60 days pass and the assessment stands.

Most math error corrections are correct. Check the notice against your return before deciding.

What to gather

  • The notice, with the explanation of the change
  • Your return as filed, with the schedule or form the notice references
  • Documents supporting the figure you reported (the W-2, the 1099, the dependent's Social Security card)
  • Your amended return, if the notice is a CP21 or CP22

How to write back

  1. CP14 response letter: A short letter that responds to a balance due notice: what you are paying, what you dispute, and what you are attaching.

Closest built pages

Before you send anything

This is general information, not tax advice. Situations differ. Check with your tax advisor before you send anything. Nothing on this page creates a client relationship.

Sources

  1. IRS, Understanding your IRS notice or letter
  2. IRS, Understanding your CP11 notice
  3. IRS, Understanding your CP12 notice
  4. IRS, Understanding your CP21A notice