IRS notices and letters: what each one means and what to do next

What an IRS notice is and why the code matters

An IRS notice is an official letter about your federal tax account. The IRS begins almost every contact by mail, and each letter carries a code: a CP number or an LT or LTR number. That code is the fastest way to know whether you are holding a bill, a warning, a proposed change or a request for information.

Once you know the code, you can look up the IRS explanation page for that notice, which says what the letter means and what response the IRS expects. If you are not sure why the envelope arrived at all, start with why you got an IRS letter.

How to read an IRS letter in the right order

Most IRS letters follow the same layout. Reading these parts in order takes a few minutes and tells you nearly everything you need.

1. Notice code and date. Look in the top or bottom right corner. The date printed there usually starts the clock for your response.
2. Tax year and form. The letter names the year and the return type, such as Form 1040 for 2024. Pull your copy of that return.
3. Amount. A bill shows tax, penalties and interest separately. A proposal such as CP2000 shows the change the IRS wants to make.
4. Response date. Many notices print a specific date. Others state a number of days from the notice date.
5. What the IRS wants. Payment, a signed response form, a missing return or documents.
6. Where to reply. The mailing address, fax number or upload instructions printed on the notice.

Keep the original letter with your tax records. The IRS asks every recipient to review the notice carefully and hold on to it, and you will need its code and date when you call, write or upload.

The balance-due sequence: CP14 to the final levy notice

When you file a return but do not pay in full, the IRS sends a series of IRS notices that grow firmer over time. The first is the CP14 balance due notice. Reminders follow as CP501 and CP503, then a CP504 notice of intent to levy, and then the final notice that gives you a hearing right.

The gap between letters varies, and a letter can be skipped when the IRS moves an account along faster. What stays the same is the direction of travel: each stage adds consequences. After the CP504, for example, the IRS may take a state tax refund, and the failure-to-pay penalty can rise from 0.5% to 1% a month if the balance is not paid within 10 days of a notice of intent to levy.

Why the early letters are the cheapest to answer

At the CP14 stage you have the most choices and the lowest cost. A short-term plan of up to 180 days has no setup fee for balances under $100,000, and a long-term plan set up online with direct debit costs $29. By the time a final notice arrives, the balance is larger and the IRS can levy wages and bank accounts after the 30-day window closes.

Enforcement and hearing-rights notices

A handful of letters carry legal weight because they trigger or protect rights. Treat any of these as urgent and note the date printed on the letter.

• CP504, Notice of Intent to Levy. Issued under Internal Revenue Code section 6331(d). It allows the IRS to levy a state tax refund, but it does not by itself give Collection Due Process rights. See our CP504 notice guide.
• LT11 or Letter 1058, Final Notice of Intent to Levy and Notice of Your Right to a Hearing. You have 30 days from the date of the notice to request a Collection Due Process hearing on Form 12153. Our page on the final notice of intent to levy covers the hearing in detail.
• CP90. Intent to levy certain assets, plus the right to a Collection Due Process hearing.
• Letter 3172. Tells you a Notice of Federal Tax Lien was filed and gives a separate 30-day hearing right; the letter states the date that window ends.
• CP523. The IRS plans to end a defaulted installment agreement and levy. Contact the IRS within 30 days of the notice date.
• CP508C. Your seriously delinquent tax debt was certified to the State Department, which can deny or revoke a passport. The 2026 threshold is $66,000; the 2027 figure is not yet announced and usually appears with the October or November inflation adjustments.

Adjustment and deficiency notices

Not every IRS letter is a bill. Some propose a change to a return that is already filed, and they come with a response window instead of a payment due date.

• CP2000. Income or payments reported by employers, banks or brokers do not match your return. The IRS calls it a proposal, not a bill. Reply within 30 days of the notice date, or 60 days if you live outside the US. Read our CP2000 notice explainer.
• CP3219A, Statutory Notice of Deficiency. You have 90 days (150 if the notice is addressed outside the US) to petition the US Tax Court, and that deadline cannot be extended. See CP3219A.
• CP11. The IRS corrected what it sees as a math or clerical error on your return, and you now owe. Ask for a reversal by the date on the notice; you have 60 days. See our CP11 notice page.
• CP22A. The IRS changed your return because you asked it to, and you now owe.
• CP59. The IRS has no record of a prior-year return. File it, or explain why you did not need to file.

IRS notice codes: full list with meanings and deadlines

This table lists the IRS notice codes this site covers, in rough order from first bill to enforcement, followed by adjustment letters. Deadlines come from the IRS explanation page for each notice.

How to know an IRS letter is real

Scammers copy the look of IRS letters, so check before you act. The IRS contacts people about taxes by mail first and notifies audits by mail only. A real notice matches a tax year you recognize and asks you to pay the United States Treasury, never a gift card, payment app or private person.

• Sign in to your IRS online account; certain notices appear there and can be viewed and downloaded.
• Check that the notice code exists on IRS.gov and that the letter describes what that page says it should.
• If a private collection agency writes to you, you should first have received IRS Notice CP40. The only agencies the IRS uses are CBE Group, Coast Professional and ConServe, and they cannot ask you to pay them directly.

Our guide to IRS letter scams walks through the warning signs in more detail.

What happens if you ignore an IRS notice?

Ignoring an IRS letter does not pause anything. Balances keep collecting interest, currently 7% a year compounded daily through December 2026 (the January to March 2027 rate is not yet announced and usually comes out in late November). Penalties keep adding up to their caps.

Ignored balance-due letters move toward a filed lien and a levy on wages or bank accounts. An ignored CP2000 becomes a statutory notice of deficiency, and if that deadline passes too, the proposed tax can be assessed and billed. Missed hearing deadlines narrow your appeal options. To guarantee your appeal rights, the IRS says to reply by the due date on the notice. Our step-by-step guide to responding to an IRS notice shows how.