Understanding your CP18 notice
The IRS believes you incorrectly claimed one or more deductions or credits and are letting you know they plan to review and correct your return.
Type of Notice
Tax return error
Why you received the CP18 notice
A CP18 is the notice the IRS sends when they find an error in credits and/or deductions on your tax return. You will receive a notice once the adjustments are made to your account if you send us any changes.
Likely next steps
As always, carefully read the notice.
If you disagree with the notice, you need to contact the IRS at the toll-free number listed on the CP18 in the top right-hand corner or by mail within 60 days.
CP18 Notice deadline
There is no deadline unless you disagree with the IRS changes. Then, you have 60 days from the date of the notice to contact the IRS.