CP10: a correction changed the estimated tax carried forward

What a CP10 means

A CP10 means the IRS corrected one or more mistakes on your return, and the correction changed the estimated tax payment you asked to have applied to next year. [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

This one matters mostly for next year. If less was carried forward than you planned, your next estimated payments may need to go up.

Why people get one

• You asked to apply an overpayment to next year, and a correction made the overpayment smaller.
• An arithmetic or credit error was fixed on the return.

First steps

1. Find what changed on the notice and compare it with your return. [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 you agree, you don't need to respond. Update your copy of the return, but don't mail it to the IRS. [1]source 1
4. Rework next year's estimated tax payments with Form 1040-ES, since less may be credited than you planned. [1]source 1
5. If you disagree, call the number printed on your notice by the date shown. [1]source 1

What not to do

• Don't keep paying next year's estimates on the old assumption.
• 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. [1]source 1

Related notices

• Related CP11 A correction that leaves a balance due.
• Related CP12 A correction that changes a refund or creates one.
• Related CP13 A correction that leaves the account at zero.

Keep reading

• Estimated tax
• Section 6213

Questions