When people say they are being audited, they usually mean one of three things: the IRS wants documents by mail, the IRS wants a meeting at one of its offices, or an IRS employee wants to meet at your home or business. These are the main types of IRS audits, and knowing which one you have tells you what to prepare and how much time you may need.
The three types
| Type | Where it happens | What it usually involves |
|---|---|---|
| Mail audit | By post, fax or an approved electronic method | Written questions about specific items such as income, expenses or itemized deductions |
| Office audit | An IRS office | Interview and review of your records for the items in question |
| Field audit | Your home, business or your representative's office | Broader review, often of a business, with more records and more time |
The IRS notes that if you have too many records to mail, you can ask for a face-to-face audit instead. The letter you receive will give the contact details and the instructions for your particular case.
Mail (correspondence) audits
A mail audit is the most common format for individuals. The letter lists the items under review and the documents that support them. You respond with copies of records, a written explanation, or both. Because everything is on paper, clear organization matters: label each document with the item it supports and keep a copy of everything you send.
For mail audits, the IRS says it can ordinarily grant one automatic 30-day extension if you ask in writing, by fax to the number on the letter or by mail. Asking early works better than asking on the due date. Our page on how to respond to an audit letter covers the steps.
Office audits
In an office audit, you or your representative meet an examiner at an IRS office. The letter lists the items to be reviewed and the records to bring. Prepare for the questions on the letter, not the whole return. Your representative can often attend in your place, and a power of attorney is how that is arranged (see Form 2848).
Field audits
A field audit takes place where your records are: your home, your business, or your accountant's or representative's office. Field audits more often involve business returns, self-employment income or larger, more complex returns, though the IRS does not limit them to those. Examiners may use IRS audit technique guides that explain how particular industries tend to keep records and where errors commonly occur. The IRS lists a representative's office as one possible location, which some business owners find less disruptive than having the examiner on their premises.
Audits versus automated notices
Some IRS letters look like audits but are processed differently.
- Underreporter matching. The CP2000 notice proposes changes after the IRS compares your return with forms it received, such as a Form W-2 or Form 1099. It is a proposal based on a mismatch, not a full examination.
- Math or processing corrections. The IRS may correct a return during processing and tell you what changed. The notice explains how to respond.
- Identity verification letters. These ask you to confirm that you filed a return. They are not audits. See our page on identity theft and the IRS.
If you are unsure which category your letter falls into, the guide to reading an IRS notice can help you identify the notice number and the deadline.
Which years are open to audit
The IRS says it can generally examine returns filed within the last three years. If it finds a substantial error, it may look at additional years, but it usually does not go back more than six years. More than three years can be open in some situations, such as when a large amount of income was left off a return. The statute of limitations page explains these time limits, and the IRS also says taxpayers should keep the records used to prepare a return for at least three years from the filing date.
How an audit ends
All three types end the same way. The IRS may accept the return as filed, propose changes you agree with, or propose changes you dispute. If you disagree, you can ask for a conference with an IRS manager, consider mediation, or request a review by the Independent Office of Appeals. See IRS Appeals for how that works.
How we can help
Whether your audit is by mail, in an office or in the field, we can read the letter, identify the exact items in question, collect and organize the records, and communicate with the examiner once you sign a power of attorney. If an audit shows that an earlier return needs correcting, we can prepare the amended return. We provide general information on this site and look at your facts when you contact us.
See IRS audit representation for more on how representation works, or contact us.
Frequently asked questions
Which type of audit is the most serious?
None is labeled that way. Field audits tend to cover more records and more time, but any audit can result in additional tax if the records do not support the return. The letter lists the items and tax years under review.
Can I ask to change a mail audit into an in-person audit?
Yes, the IRS says that if you have too many records to mail, you can request a face-to-face audit. Ask the contact listed on your letter.
Does a refund trigger an audit?
The IRS says that a refund alone does not necessarily cause a return to be selected. Selection can come from screening, random sampling or a related examination of another taxpayer.
Is a CP2000 an audit?
It is an automated comparison between your return and information the IRS received from other payers. It is a different process from an examination, but it still has a response deadline, so read it promptly.
What if I do not respond at all?
The IRS says that if you miss the due date, it will complete the audit and send a report with its proposed changes. That report may include additional tax, interest and penalties based on what the IRS has in its file.
Official sources
- IRS: IRS audits
- IRS: Topic no. 305, Recordkeeping
- IRS: Publication 556, Examination of returns, appeal rights and claims for refund
This page is a plain-language summary. The official source controls if there is any difference.
General information only, not tax, legal or accounting advice for your situation. Rules, limits and deadlines change; confirm the current rules with the official source or a qualified professional before you act. Reading this page does not create a professional relationship with CPA Tax Payroll and Accounting Corp.