IRS audit basics: Mail, field audits, Letter 566 and appeals

The short answer

An IRS audit is an examination of whether a return reports the right tax. It is not automatically a bill, an accusation of fraud or a visit to your home. The IRS may examine records by mail, at an IRS office, or in a field interview at a home, business or representative's office. Selection alone does not establish that your return is wrong.

Your immediate job is to identify the tax year, the items questioned, the response date and the office handling the examination. Verify the letter, organize the requested records and answer through the authorized channel. If the IRS later proposes changes, decide which facts or legal conclusions you dispute and preserve the appeal opportunity described in that later letter.

Do not confuse three stages: a request for evidence, a proposed audit adjustment with administrative appeal rights, and a statutory notice of deficiency with a court deadline. Asking for more time at one stage does not automatically extend another. The IRS audit overview explains the examination process; your actual correspondence identifies your current step.

Correspondence, office and field audits

A field audit describes the examination setting. It is not the same as a visit by a collection revenue officer about already-assessed tax, and it does not mean a criminal investigation has begun. If contact suggests possible criminal exposure or you are being asked about knowingly false information, seek advice from an appropriately qualified tax attorney before providing substantive answers.

The IRS says it initially notifies taxpayers of an audit by mail, not by initiating the audit over the telephone. Later calls can be legitimate. Independently verify unexpected contact using our notice and scam-verification guide; neither caller ID nor a familiar letter number proves authenticity.

For a mail examination with too many records to send, the IRS says you may request a face-to-face audit. That is a request, not permission to stop responding while you wait. Confirm how to handle the outstanding deadline with the examining office.

Letter 566: Read the complete number and enclosures

Letter 566 is associated with an examination request. Preserve any suffix and read the complete letter: the current code-specific public instructions checked for this guide are for Letter 566-T, not a promise that every 566 variant uses identical forms, channels or timing. The Letter 566 guide separates the verified 566-T instructions from that broader context.

For 566-T, the IRS says it needs documents supporting items claimed on your federal income tax return. Read the enclosed forms and questionnaires to identify the actual issue. Do not assume that every deduction, every business account or every tax year is under examination merely because you received the letter.

The IRS 566-T instructions call for readable copies, completed questionnaires where enclosed, and Form 14817, Reply Cover Sheet. Organize the documents by the questioned items and send the requested material together to reduce confusion. Retain originals and a complete duplicate of your submission.

Check the deadline rather than counting from this guide. The current IRS 566-T webpage says both “within 30 days of the date of the letter” and, later, “within 30 days of the date you received your letter.” Those are different starting points. Use the response date on your actual letter, contact the examiner promptly if it is unclear, and do not rely on the later reading to delay your response.

The page describes Secure Messaging if you qualify, fax to the letter's number, the official Document Upload Tool, and mail to the address on the letter. Use only the option available for your case. Follow the cover-sheet instructions; never upload taxpayer records to TaxRZR or email them to a stranger offering to resolve the audit.

Build an evidence packet the examiner can follow

Start with a copy of the filed return and the specific request. Make a short index matching each IRS question to the return line, your explanation and its supporting pages. A bank withdrawal may show money moved without establishing why an expense qualifies for a deduction; explain the tax connection as well as the payment.

For example, if a business expense is questioned, identify the transaction, amount, business purpose and records supporting the position. If a dependent-related item is questioned, answer the actual eligibility and documentation questions in the enclosure rather than sending unrelated business receipts. This is an organizational example, not a universal list of evidence sufficient for a deduction or credit.

• Number the pages and clearly identify the relevant tax year and case as the IRS instructions require.
• Check that scans include all pages and are legible. Supply requested questionnaires, not just a cover letter saying you disagree.
• Explain missing records honestly and ask what other evidence may be considered. Do not invent receipts or alter documents.
• Keep the complete packet and submission confirmation. Record conversations and promised follow-up in the IRS communication log.

Send confidential identifiers only where the official instructions require them and through the verified channel. Do not publish your return, full transcript or notice in a public forum. An acknowledgment is useful evidence of receipt, but it is not an agreement with your position or an extension of a later deadline.

If you need more time—or have already missed the reply date

Contact the examining office before the due date. For mail audits, the general IRS audit page describes a written fax or mail extension request and ordinarily a one-time 30-day extension. The 566-T page also describes requests through eligible Secure Messaging, the upload tool or the telephone number on the letter. Follow the instructions for your case, document the request and confirm its status; do not invent an extension date yourself.

For an in-person audit, contact the assigned examiner, or the examiner's manager if needed. An extension to send evidence is not a blanket extension of the assessment period, an administrative protest deadline or the time to petition the Tax Court.

Ignoring a request can cause the IRS to complete the examination without your supporting evidence and propose disallowing the items questioned. If the reply date has passed, contact the examiner immediately and identify whether the case remains an open audit, has a proposed report, or already has a statutory notice. Do not wait for a new reminder before checking which rights remain available.

Read the audit result before signing

The IRS describes three outcomes: no change, agreed changes, and changes you disagree with. Read the report and ask the examiner to explain anything unclear. Compare the proposed additional tax and penalties with the facts and documents you provided.

If you agree, understand what the agreement form does before signing and address any resulting balance. If you disagree, identify exactly which adjustments remain disputed and why. A disagreement supported by specific facts and applicable law is different from saying the bill is unaffordable.

Letter 525 commonly accompanies proposed examination changes and a general 30-day administrative appeal opportunity. Letter 950 can cover a broader range of examination outcomes and tax types. Neither should be treated as interchangeable with a statutory notice of deficiency. Follow the rights stated in the document you actually received.

How to request an audit appeal

You may ask for an examiner's manager conference. The IRS Independent Office of Appeals may also consider an unresolved dispute when the case qualifies and there is sufficient time. Under the IRS appeal instructions, send the request to the IRS office and address identified in the letter offering appeal rights—not directly to an Appeals office.

The request is generally due within 30 days of the letter, but the actual letter's instructions control. An informal call to say you disagree is not a substitute for a required written protest. Provide your evidence to Examination rather than withholding it for Appeals. The originating office considers the protest and forwards an unresolved case as appropriate.

For an ordinary examination, the IRS permits a Small Case Request when proposed additional tax and penalty for each tax period total $25,000 or less, subject to exclusions. Employee plans, exempt organizations, S corporations and partnerships do not qualify for that procedure. Follow the letter and use Form 12203 or an allowed written statement when appropriate. Larger or excluded cases generally require a formal written protest; use the current Publication 5 instructions for its contents, statements and signatures.

Do not confuse this administrative $25,000 test with the Tax Court's separate small-tax-case rules. Do not choose a procedure simply because your current account balance falls below a number. Consult a qualified representative when the case type, calculation or remaining time is uncertain.

A notice of deficiency is a separate court deadline

A later statutory notice, such as the CP3219 notice family, generally offers a deficiency-case petition period of 90 days, or 150 days if the notice is addressed to a person outside the United States. Do not assume your case has the longer period merely because you are traveling.

Read the legal notice and the Tax Court's current filing guidance. Electronic petitions generally must reach the Court by 11:59 p.m. Eastern time on the last filing date. Mailing, approved delivery methods, holidays, disaster relief and unusual deadline situations require attention to the actual rules; this guide does not calculate your filing deadline.

Continuing to send documents to the IRS, asking for audit reconsideration or waiting for an examiner's callback does not preserve the court deadline. A petition is filed with the Court, not sent to the examiner as another audit reply. If time is short or already passed, seek prompt qualified advice rather than assuming late filing will be accepted.

If tax has already been assessed or you cannot pay

Audit reconsideration may be available for some assessed examination liabilities when, for example, relevant information was not previously considered. The IRS describes this process for assessed tax that remains unpaid; if you have already fully paid, check refund-claim procedures and deadlines instead. It is not the same as a timely protest of a proposed adjustment. Read the IRS reconsideration process before using the audit-reconsideration model letter. That template does not replace a 566-T questionnaire, an appeal protest or a Tax Court petition.

An audit establishes whether the tax is correct; collection addresses payment of an assessed liability. Collection Due Process and collection appeal procedures have different triggers and forms. Form 12153 is not the ordinary audit protest form. An existing collection deadline for another liability can continue while an examination is underway.

If you accept the tax but cannot pay, examine installment agreements and hardship status. Inability to pay alone is not a factual or legal reason to reverse an audit adjustment.

What to do this week

1. Verify the sender and save every page and the envelope. Record the full letter number, tax year, examiner and response date.
2. Match each requested item to your return and supporting records. Keep a missing-information list.
3. Request more time promptly if needed, using the verified office's instructions, and keep proof.
4. Send the organized packet through the authorized channel; retain originals, copies and delivery evidence.
5. Review any proposed changes and the letter's appeal instructions before signing an agreement.
6. If you receive a statutory notice, check court filing rights immediately. Seek qualified help for an urgent deadline, substantial dispute or complex business examination.

You may represent yourself or engage an eligible representative. Verify credentials and scope using our professional-selection guide. Representation before the IRS and admission to practice before the Tax Court are different qualifications. Low Income Taxpayer Clinics may help eligible taxpayers; availability and eligibility vary.

Does an IRS audit mean I did something wrong?

No. Selection alone does not establish an error or fraud. The IRS uses several selection methods, including screening and related examinations. The outcome depends on the facts, applicable rules and supporting records.

Is Letter 566 a bill or a levy notice?

The verified 566-T instructions describe an audit request for supporting documents, not a bill or levy notice. Preserve the full number and suffix; other correspondence and existing liabilities may create separate obligations.

Can I appeal an audit because I cannot afford the tax?

An audit appeal addresses a disputed IRS decision using facts and law. Inability to pay alone belongs in payment or hardship discussions, not a protest claiming that a correct tax calculation is wrong.

Does requesting more time extend my Tax Court deadline?

No. An examiner's extension for sending records does not extend the separate petition period on a statutory notice of deficiency. Continuing to work with the IRS does not replace filing a timely petition with the Court.

Can I use the reconsideration letter for my first audit response?

Not as a substitute for the documents, cover sheet and questionnaires your audit letter requests. The model reconsideration letter concerns a later assessment-review process; check eligibility and preserve any open protest or court deadline separately.

Official sources and review status

Sources checked October 30, 2026 (US Eastern time). Prepared by the TaxRZR editorial team; professional review pending. This is general federal tax education, not a determination of your liability, representation rights or filing deadline.

• IRS: Audits, records, extensions and outcomes
• IRS: Understanding your 566-T Letter
• IRS: Considering an appeal
• IRS: Preparing a Request for Appeals
• U.S. Tax Court: Starting a case
• IRS Internal Revenue Manual: Statutory notices of deficiency and separate petition periods
• IRS: Audit reconsideration for correspondence examinations

See Source Notes for the dated publication record. Dates advance only after an actual source check, not automatically.