Got a letter from the IRS? Know what it wants.

First, three things

• Find the notice number. It’s printed in the top or bottom right corner, like CP2000 or LTR 5071C.
• Find the date and the deadline. Missing it can add interest and penalties, or let the IRS make its change without hearing from you.
• Make sure it’s real. The IRS starts contact by mail, not by text, email or social media.

The letters people get most

CP2000

Proposed changes to your returnThe income or payments on forms the IRS received (W-2s, 1099s) don't match your return, so it proposes more tax. This is a proposal, not a bill or an audit.Respond: About 30 days from the notice date

CP14

You have a balance dueThe first bill for tax you owe for this year.Respond: 21 days from the notice date (10 business days if you owe $100,000 or more)

CP501

Reminder of a balance dueA reminder that you still owe tax. Interest and penalties keep adding up.Respond: Go by the notice: it says if and when to respond

CP503

Second reminder of a balance dueThe second reminder that you owe tax. If it stays unpaid, the IRS moves toward collection.Respond: Go by the notice: it says if and when to respond

CP504

Notice of intent to levyThe IRS plans to take your state tax refund and may take other property or rights to property to pay what you owe.Respond: About 30 days from the notice date

CP05

We're reviewing your returnThe IRS is checking your income, withholding or credits before it sends your refund. You don't need to do anything yet.Respond: Go by the notice: it says if and when to respond

LTR 5071C

Verify your identityA return was filed with your name and Social Security number, and the IRS needs you to confirm it was you before it finishes processing.Respond: Go by the notice: it says if and when to respond

CP12

Math error changes; refund changedThe IRS fixed what it sees as a mistake on your return, which changed your refund (or created one).Respond: About 60 days from the notice date

CP11

Math error changes; you oweThe IRS fixed what it sees as a mistake on your return, and now you owe tax.Respond: About 60 days from the notice date

CP2501

Income on your return may not matchAn early letter: forms the IRS received show income that may be missing from your return. It wants an explanation before it proposes changes.Respond: About 30 days from the notice date

If you disagree

You can. Write back by the date on the notice, send copies (not originals) of what shows why, and use the address, fax number or upload link the notice gives. For a CP2000, say so on its response form; don’t file an amended return for it. Keep a copy of everything you send.

When to get help

For an audit, a notice of deficiency (CP3219A) or a court petition, work with a CPA or an enrolled agent.