The short answer
Most IRS letters are about a specific, fixable issue: a balance due, income that doesn't match, or a missing return. Find the notice number in the top or bottom right corner, make sure the letter is real, and respond by the date on it.
Last reviewed: October 2026
Step 1: Find the notice number
Look in the top or bottom right corner for something like "CP2000" or "LTR 5071C." That code tells you what the letter is about.
Step 2: Make sure it's really from the IRS
- The IRS usually starts contact by mail, not by text, email or social media.
- The IRS won't demand payment by gift card, wire transfer or cryptocurrency, and won't threaten to send the police.
- To check, sign in to your IRS online account at IRS.gov, or call the IRS using a number from IRS.gov, not one from a suspicious letter.
Step 3: Know the common ones
- CP14: you have a balance due.
- CP501, CP503: reminders that a balance is still unpaid.
- CP504: notice of intent to levy. Take this one seriously.
- CP2000: the income on your return doesn't match what the IRS received. It's a proposal, not a bill, and you can disagree.
- CP59: the IRS has no return from you for a year.
- CP3219A: a notice of deficiency. It has a strict 90-day deadline.
- Letter 5071C or 4883C: the IRS wants to confirm your identity before processing your return.
Step 4: Respond by the date on the letter
If you agree, follow the instructions. If you don't, say so in writing with your documents before the deadline. Missing the date can cost you options later.
Official source: IRS: Understanding your notice or letter.
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Disclaimer: This page is general information, not tax advice. Every situation is different, and tax rules change. Reading this page doesn't make you a client.