What Is an IRS Notice? How to Respond

An IRS notice is an official communication about a federal tax return, payment, refund, identity issue, information request, proposed adjustment, assessed balance, or collection matter. Each notice has a code or letter number and instructions tailored to the issue.

Receiving a notice does not automatically mean the taxpayer is being audited or owes the amount shown. Some notices request information, explain an account change, verify identity, correct a math error, propose additional tax, or confirm a payment. The first task is to identify exactly what the notice says.

What to check first

Review the entire notice and locate:

• The notice or letter number, often beginning with CP or LTR
• Taxpayer name and masked taxpayer-identification number
• Tax form and tax year involved
• Explanation of the issue and any proposed or completed change
• Amount shown and how it was calculated
• Response deadline
• Address, fax number, upload option, or phone number assigned to the notice
• Appeal, petition, payment, or documentation instructions

Compare the notice with the filed return, IRS transcript when appropriate, payment confirmations, and the source documents for that year. Do not assume the IRS or the return is correct until the difference is reconciled.

Is the notice real?

The IRS normally initiates contact through U.S. mail, although taxpayers who opt into an online account may receive certain electronic notifications. Verify a suspicious communication by going directly to IRS.gov or using a known IRS contact method rather than clicking an unexpected link.

Warning signs include demands for payment by gift card, cryptocurrency, wire transfer to an individual, or threats of immediate arrest. A real notice should identify the tax issue and provide established rights and response methods.

Proposal, assessment, and bill are different

How to respond

Follow the instructions for that specific notice. If the notice is correct, the taxpayer may need to sign a response, provide information, make a payment, or simply keep the letter. The IRS states that no reply is needed unless the notice asks for one.

If the taxpayer disagrees, prepare a concise explanation tied to each disputed item and include copies — not irreplaceable originals — of supporting records. Keep a complete response package and delivery proof. Use the exact upload, fax, or mailing method shown on the current notice.

Call before the deadline if more time is needed and the notice permits an extension request. A phone conversation does not replace a written response when the notice requires documents or a signed form.

A practical example

Suppose the IRS sends Maria a notice showing $4,000 of proposed additional tax. The notice says a brokerage reported $18,000 of proceeds that did not match her return.

Maria finds the brokerage statement and confirms that the investments cost $16,500. The notice may have treated basis as zero because the IRS did not receive or match it. Her response should reconcile each reported transaction and provide the supporting basis information. It should not simply say, "I disagree."

If the IRS accepts the documentation, the proposal may be reduced or removed. If some tax remains, Maria can pay, evaluate a payment plan, or use the appeal rights stated in the next communication.

California consequences

An IRS notice concerns federal tax. It is not an FTB notice, and paying the IRS does not pay California. However, a final federal change can alter California income, deductions, credits, basis, or carryovers.

After the federal matter is resolved, determine whether a California amended return or report of federal change is required. Do not amend California merely because an IRS proposal arrived; first identify whether the federal result becomes final and whether it changes the California return.

When representation may help

Professional help may be useful when a deadline is close, records are missing, the amount is material, multiple years are affected, a notice of deficiency is involved, or the issue could create California changes. An enrolled agent, CPA, or attorney with the appropriate experience may represent a taxpayer before the IRS after receiving valid authorization, commonly through Form 2848.

Common mistakes

• Ignoring the notice or missing the response date
• Paying before checking the calculation
• Mailing original records
• Responding to the wrong IRS address
• Treating a proposal as a final bill
• Filing an unnecessary amended return
• Forgetting to consider California effects
• Assuming a phone call preserved appeal or petition rights
• Falling for a scam that imitates IRS language

Frequently asked questions

Related terms

• CP2000 Notice
• Notice of Deficiency
• Tax Transcript
• Installment Agreement
• Enrolled Agent
• IRS Audit

Official sources

• IRS — Understanding your IRS notice or letter
• IRS — How to know it is the IRS
• IRS — Your rights as a taxpayer
• California FTB — Correct an income tax return

The definitions and examples on this page are for informational purposes only and do not constitute tax advice. Tax laws change frequently and individual circumstances vary. Consult a qualified tax professional before making decisions based on this content.