What Is a Tax Audit? Types, Triggers, and How to Respond
Last updated 04/27/2026 by
Ante Mazalin
Edited by
Andrew Latham
Summary:
A tax audit is a formal review of a taxpayer’s financial records and filed tax return by the IRS or a state tax authority to verify that income was reported accurately and deductions were taken correctly.
Audits take three distinct forms, each with different levels of intensity.
- Correspondence audit: The most common type — conducted entirely by mail, typically requesting documentation for one or two specific line items on your return.
- Office audit: An in-person review at an IRS office, covering a broader set of issues than a correspondence audit and requiring you to bring records and documentation.
- Field audit: The most thorough type — an IRS agent visits your home or business to examine records in depth, most often used for complex returns or businesses with significant income.
Most people will never face an audit, but receiving an IRS notice in the mail can still feel alarming. Understanding what the different types of audits involve — and what actually triggers them — makes the process far less intimidating and far easier to handle if it does arrive.
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What Triggers a Tax Audit?
The IRS selects returns for audit through a combination of automated scoring, data matching, and random selection. According to the IRS, the overall audit rate for individual returns is well below 1% — but certain patterns elevate that risk significantly.
High income: Audit rates climb sharply above $500,000 in reported gross income and again above $1 million. The IRS dedicates more scrutiny to returns where potential recovery is highest.
Large or unusual deductions: Deductions that are disproportionately large relative to income — especially charitable contributions, business meal expenses, and home office deductions — stand out in the IRS’s automated scoring system (called the Discriminant Function System, or DIF).
Self-employment income: Schedule C filers report income and expenses without employer verification, which makes them statistically higher-risk. Cash-intensive businesses — restaurants, contractors, freelancers — receive additional scrutiny.
Unreported income: The IRS receives copies of every 1099, W-2, and financial institution report filed on your behalf. If income that appears on those third-party forms doesn’t show up on your return, an automated mismatch triggers a notice.
Round numbers: Consistently round figures on expense lines (exactly $5,000 in meals, exactly $10,000 in travel) can signal estimates rather than documented actuals.
Related audits: If a business partner, investor, or employer is audited and their records reference you, the IRS may open a parallel examination.
Types of IRS Audits
| Audit Type | How It Works | Typical Scope |
|---|---|---|
| Correspondence audit | IRS sends a letter requesting documentation for specific items | One or two line items; resolved by mail |
| Office audit | You meet with an IRS agent at a local IRS office | Several issues; you bring records to the meeting |
| Field audit | IRS agent visits your home or place of business | Comprehensive examination of records and operations |
| Taxpayer Compliance Measurement Program (TCMP) | Random full audit used to build statistical models | Every line of the return verified with documentation |
The vast majority of audits are correspondence audits — the IRS sends a letter, you send back documentation, and the matter is resolved without ever speaking to an agent. Office and field audits are far less common and tend to involve more complex tax situations.
What Happens During a Tax Audit?
An audit begins with a written notice — the IRS does not initiate audits by phone or email. Any call or email claiming to be an IRS audit notice should be treated as a potential scam.
The notice specifies which tax year is under review, which items are being questioned, and what documentation is requested. For a correspondence audit, you respond in writing with supporting records. For an office or field audit, you’ll be given a date and a list of documents to bring or have available.
During the examination, the IRS agent reviews your records against your reported figures. You have the right to be represented by a tax professional — a CPA, enrolled agent, or tax attorney — who can speak on your behalf throughout the process.
Pro Tip
Never ignore an IRS audit notice. Missing the response deadline — typically 30 days for correspondence audits — results in the IRS automatically assessing additional tax based on their findings, with no opportunity to present your documentation. If you need more time to gather records, request an extension in writing before the deadline. A tax relief professional can handle all communication with the IRS on your behalf, which is especially valuable in office or field audits where what you say can expand the scope of the review.
How to Respond to a Tax Audit
How to respond to an IRS audit notice
Follow these steps from the moment you receive an IRS audit notice.
- Read the notice carefully. Identify the tax year, specific items being questioned, the deadline for response, and the address or contact information for the examining unit.
- Gather your documentation. Pull together bank statements, receipts, invoices, and records supporting every item being questioned. Organize them to correspond directly to the items in the notice.
- Consider professional representation. For anything beyond a simple one-item correspondence audit, an enrolled agent, CPA, or tax attorney can represent you before the IRS and prevent scope creep during the examination.
- Respond by the deadline. Reply in writing to correspondence audits; confirm your appointment for office or field audits. Request a written extension if you need more time — IRS agents typically grant reasonable extensions.
- Provide only what’s requested. Don’t volunteer additional information or documentation beyond what the notice asks for. Expanding the conversation can expand the audit’s scope.
- Review the IRS findings carefully. If the auditor proposes additional tax, compare it line by line to your records before agreeing. Errors in the IRS’s favor do occur.
- Appeal if you disagree. You have the right to appeal any proposed changes — first within the IRS Appeals Office, and then through the U.S. Tax Court if needed.
Possible Audit Outcomes
An audit can resolve in one of three ways.
No change: Your records support your return as filed, and the IRS closes the case with no additional tax owed. This is the outcome when documentation is thorough and organized.
Agreed changes: The auditor identifies discrepancies, proposes additional tax and possibly penalties, and you agree with the findings. You sign an agreement form and arrange payment. If you can’t pay the full amount immediately, an installment agreement or offer in compromise may be available.
Unagreed changes: You dispute the IRS’s proposed adjustments. The case moves to the IRS Office of Appeals — an independent body that resolves disputes without litigation. If Appeals doesn’t resolve it, you can petition the U.S. Tax Court.
Unpaid audit assessments that go unresolved can result in the IRS filing a tax lien against your property and eventually escalating to a tax levy to collect what’s owed.
How to Reduce Your Audit Risk
No strategy eliminates audit risk entirely — the IRS does conduct random audits — but these practices reduce the most common triggers.
Keep detailed records year-round. For every deduction you take, retain the receipt, bank statement, or documentation that supports it. The IRS standard for substantiating business expenses is contemporaneous records — documents created at the time of the transaction, not reconstructed later.
Report all income. Every 1099, W-2, and brokerage statement the IRS receives gets matched against your return. Unreported income — even small amounts — is one of the fastest ways to trigger an automated notice.
Be precise with home office and vehicle deductions. These are among the most scrutinized deductions. The home office deduction requires exclusive and regular use of the space for business — a guest room that doubles as an office doesn’t qualify.
File on time. Late returns can attract additional scrutiny. If you need more time, file for an extension — which extends your filing deadline, not your payment deadline.
Work with a qualified tax preparer. Returns prepared by credentialed professionals (CPAs, enrolled agents) are statistically less likely to contain errors that attract attention. Comparing tax preparation and relief services on SuperMoney lets you find providers suited to the complexity of your situation.
Key takeaways
- A tax audit is a formal IRS review of your return and financial records — it does not mean you’ve done something wrong or that additional tax is certain.
- The three types are correspondence (by mail), office (in person at an IRS office), and field (IRS agent visits you). Correspondence audits are by far the most common.
- The IRS never initiates an audit by phone or email — all legitimate audit notices arrive by mail.
- Key audit triggers include high income, large deductions relative to income, self-employment income, and mismatches between third-party income reports and your return.
- Respond to every notice by the deadline. Missing it results in automatic tax assessment with no opportunity to dispute.
- Unpaid balances from an audit can escalate to a tax lien and then a tax levy if left unresolved.
- You have the right to professional representation and to appeal any proposed changes through the IRS Appeals Office or U.S. Tax Court.
Frequently Asked Questions
How far back can the IRS audit you?
The IRS generally has three years from your filing date to audit a return — the standard statute of limitations. That extends to six years if you underreported income by more than 25%. There is no time limit if the IRS suspects fraud or if you never filed a return at all.
What happens if you can’t afford to pay after an audit?
If an audit results in additional tax you can’t pay immediately, the IRS offers installment agreements, currently-not-collectible status for genuine hardship cases, and the offer in compromise program for qualifying taxpayers. Ignoring the balance leads to penalties, interest, and eventually a tax lien. For taxpayers also managing other unsecured debts, a debt settlement plan can help prioritize obligations alongside a tax resolution strategy.
Does getting audited mean you did something wrong?
Not necessarily. The IRS selects some returns purely at random as part of statistical compliance programs. Many audits close with no change to the original return. Receiving an audit notice means the IRS wants to verify your information — not that they’ve already concluded you underpaid.
Can the IRS audit the same return twice?
Generally no. The IRS policy is to avoid re-examining a return that has already been audited for the same tax year unless there’s a specific reason — such as new information or evidence of fraud. This protection applies once the original audit is fully closed.
Do I need a lawyer for a tax audit?
For a simple correspondence audit requesting documentation for one deduction, you likely don’t need legal representation. For office or field audits, complex returns, or situations involving potential fraud, a tax attorney or enrolled agent provides significant value — they know what to say, what not to volunteer, and how to negotiate with auditors.
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