What it means
The IRS found what it believes is a math or reporting error on your return, corrected it, and now says you owe tax.
What to do now
Compare the IRS changes with your return line by line. If you agree, pay or set up a plan. If you don’t, you can ask the IRS to reverse the change.
Deadline
Usually 60 days from the notice date to dispute the change. Always go by the date printed on your notice.
Last updated October 15, 2026.