First IRS balance due notice
A CP14 is a notice that the IRS says you owe money on unpaid taxes. It is usually the first in a series of balance reminders.
Interest does not build if you pay in full by the date on the notice. After that date, interest builds on what is unpaid. A late payment penalty can also apply if you cannot pay the full amount.
Call the number in the help section of your notice, and have your records ready. Useful items include cancelled checks, proof of payment, or an amended return. You can also reply in writing with copies of your proof.
The IRS keeps sending reminders, and collection can escalate. Later notices include CP503 and CP504. Acting on the first notice is the cheapest time to act.
This guide is general information, not tax or legal advice. Your notice is the final word on your dates and amounts. If you are unsure, see when to get professional help.