An IRS audit is a review of your tax return to check that your income, deductions and credits are reported correctly. The word sounds frightening, but many audits are narrow. They often happen by mail and ask you to back up a few specific items. Being picked does not mean the IRS thinks you did something wrong. If you answer on time and send organized records, you give yourself the best chance of a quick, fair result.
How the IRS picks returns for audit
The IRS says it selects returns in two main ways:
- Random selection and computer screening. Your return is compared against "norms" for similar returns. Those norms come from statistical studies of randomly audited returns under the IRS National Research Program.
- Related examinations. If your return involves a person or business that is being audited, such as a business partner or an investment, your return may be pulled in too.
The IRS also notes that amended returns are screened and can be selected. Getting a refund, by itself, is not a reason for an audit.
A different kind of letter is the automated income-matching notice, like the CP2000. It compares your return with W-2s and 1099s and proposes changes. It is handled differently from an exam run by an auditor, but you should take it just as seriously.
The three types of audits
| Type | Where it happens | What it usually covers |
|---|---|---|
| Correspondence (mail) audit | By mail | A few items, such as income, certain expenses, itemized deductions or credits |
| Office audit | At an IRS office | More items, or items that are easier to explain in person |
| Field audit | At your home, business or your representative's office | Business returns or more complex returns |
Mail audits are common and usually the simplest. The first letter is often a Letter 566 or, for refundable credits like the Earned Income Tax Credit, a CP75. If you have too many records to mail, the IRS says you can ask for a face-to-face audit instead.
In-person audits are held either at an IRS office (an office audit) or at your home, business or your representative's office (a field audit). The IRS employees who audit returns in the field are called revenue agents, and the IRS says they usually contact you by mail first.
How you will be contacted
The IRS says it notifies you of an audit by mail and "won't initiate an audit by telephone." After that first letter, an auditor may call you to schedule or follow up. A revenue agent who visits in person carries an IRS credential and an HSPD-12 card, which you can ask to see. If someone calls out of the blue saying you are being audited and demands payment, treat it as a likely scam. Our guide to IRS scams explains how to check.
How far back the IRS can go
The IRS says it can generally include returns filed within the last three years in an audit. If it finds a substantial error, it may add earlier years, but it usually does not go back more than six years. Most audits cover returns filed in the last two years. For the full rules, including the exceptions for fraud and for returns that were never filed, see our guide to the IRS statute of limitations.
That is also why the IRS asks you to keep the records you used to prepare a return for at least three years from the date you filed it.
What to do when you get an audit letter
- Read the letter closely. Note the tax year, the items under review, the documents requested, and the response date. Keep the envelope.
- Confirm the letter is real. Check the notice number on the IRS "Understanding your IRS notice or letter" page or in your IRS Online Account. Call only the number on IRS.gov or on the letter.
- Work out your deadline. Mail audits usually give you a set number of days from the letter date. If you need more time, the IRS says a one-time automatic 30-day extension is ordinarily available by fax or mail. For an in-person audit, ask your auditor or the auditor's manager.
- Gather records for each item. Send receipts, bank and card statements, invoices, mileage logs, canceled checks, school or medical records, or anything else that proves the amount. Organize them by the item they support.
- Write a short cover letter. List each item in question and the documents you are sending for it. Put your name, tax ID and tax year on every page.
- Send copies, never originals. Use the method the letter allows: mail (with tracking), fax, or the IRS Document Upload Tool if your letter mentions it. Keep a full copy of what you sent.
- Confirm it arrived. The IRS suggests confirming receipt. If your letter lists a contact number, you can also check audit status in your Online Account for certain mail audits.
Counting the days. Say your audit letter is dated October 1, 2026, and asks for a reply within 30 days. Thirty days from October 1 is October 31, 2026. If you need more time, ask for the extension before that date, not after.
If you miss the deadline, the IRS says it completes the audit with the information it has and sends a report with the proposed changes. You still have options after that, but it is far easier to respond the first time.
Your rights during an audit
IRS Publication 1 lists the Taxpayer Bill of Rights. During an audit, the most useful rights are:
- The right to know why the IRS is asking for information and how it will be used.
- The right to professional and courteous treatment.
- The right to privacy and confidentiality about your tax matters.
- The right to representation. You can represent yourself or have an authorized representative, such as a CPA, enrolled agent or tax attorney, deal with the IRS for you. The representative needs a signed Form 2848. See our guide to choosing a tax professional and Form 2848.
- The right to appeal IRS decisions, both within the IRS and in court.
How long an audit takes
There is no fixed length. The IRS says it depends on the type of audit, how complex the issues are, how quickly information is available, scheduling, and whether you agree with the findings. Answering fully and on time is the one part of that list you control.
Sometimes the IRS asks you to extend the time it has to assess tax (the statute of limitations). The IRS says you do not have to agree. If you refuse, though, the auditor will have to decide based on the information already provided. An extension can give you more time to gather documents or appeal. This is a good moment to talk to a professional.
How an audit ends
The IRS describes three outcomes:
- No change. You backed up every item and nothing changes.
- Agreed. You accept the proposed changes and sign the exam report. If you owe, you can pay or set up a payment plan. See IRS payment plans and what to do if you can't pay.
- Disagreed. You do not accept some or all changes.
If you disagree with the result
You have several paths, and you can use more than one:
- Ask to speak with the auditor's manager. Many disputes end here.
- Ask for mediation. The IRS offers alternative dispute resolution options for some cases.
- Appeal. The IRS Independent Office of Appeals is separate from the office that audited you. You usually start this by answering a 30-day letter, such as a Letter 525 or Letter 950. According to Publication 3498-A, if the amount in dispute is $25,000 or less per tax period, you can make a small case request (Form 12203 or a short written statement). Larger amounts generally need a formal written protest.
- Go to the U.S. Tax Court. If the case is not settled, the IRS sends a Statutory Notice of Deficiency, often a CP3219A. You usually have 90 days from the notice date to petition the Tax Court, and the IRS cannot extend that window. Tax Court lets you dispute the tax before you pay it. Simplified "small tax case" procedures are available when the amount in dispute is $50,000 or less for a tax year.
If you agree to the changes at first but later find documents that would have helped, you may be able to reopen the audit. Our guide to audit reconsideration explains how.
When to get help
You can handle a simple mail audit yourself. Consider a CPA, enrolled agent or tax attorney if the audit is in person, covers a business or several years, involves large amounts, or if you are asked to extend the statute of limitations. If your income is limited, a Low Income Taxpayer Clinic may help for free or a small fee. If you are self-employed, see our self-employed hub for record-keeping tips. An optional audit response kit is available on this site, but you do not need it to respond well.
Frequently asked questions
Will the IRS call me to tell me I'm being audited?
No. The IRS says it notifies you of an audit by mail and won't start an audit by phone. An auditor may call later about an audit you already know about from a letter. If you are unsure, call the number on IRS.gov, not one given by the caller.
Does an audit mean I'm being accused of fraud?
No. An audit is a civil review, usually of specific items on your return. Returns are often picked by computer screening or because they are linked to another audited return. Criminal cases are handled by IRS Criminal Investigation, a separate division whose special agents do not work civil audits.
Can I get more time to answer an audit letter?
Usually, yes. For mail audits, the IRS says a one-time automatic 30-day extension is ordinarily available by fax or mail. For in-person audits, ask your auditor or the auditor's manager. Ask before the deadline passes.
What if I don't have all my receipts?
Send what you have and explain the gap. Bank and card statements, canceled checks, calendars, emails and statements from third parties can help back up an expense. Rebuilding records from other sources is common. A tax professional can help you judge what is enough.
Do I have to go to the audit meeting myself?
Not always. A representative with a signed Form 2848, such as a CPA, enrolled agent or attorney, can generally attend for you. The IRS can still ask to speak with you in some situations.
Can I check the status of my audit online?
For certain mail audits, yes. The IRS says you can view audit status in your IRS Online Account if your letter lists a contact number. See our guide to IRS transcripts and your Online Account.
Sources
- Internal Revenue Service (IRS), "IRS audits". irs.gov
- IRS, Publication 3498-A, "The Examination Process (Audits by Mail)". irs.gov
- IRS, Publication 1, "Your Rights as a Taxpayer". irs.gov
- IRS, "How to know it's really the IRS calling or knocking on your door". irs.gov
- IRS, Instructions for Form 2848. irs.gov
IRSV.com is an independent guide and is not affiliated with the IRS. This page is general information, not tax or legal advice. Rules change; confirm details on IRS.gov or with a tax professional. Found an error? Tell us.
