An IRS audit is far less likely than the headlines suggest — overall audit rates are low — but certain patterns reliably raise your odds. Knowing the common audit triggers helps you file cleanly and, if you are selected, understand why. Here are nine of the most frequent, along with how to protect yourself.
1. Unreported income
This is the big one. The IRS receives a copy of every W-2 and 1099, and its automated matching program flags returns where reported income does not match. Leaving off a 1099 — even by accident — is among the most common triggers. Always reconcile your return against every form you (and the IRS) received.
2. Large or unusual deductions
Deductions that are disproportionately large relative to your income stand out. A taxpayer earning $60,000 claiming $30,000 in charitable gifts invites scrutiny. The deductions may be perfectly legitimate — but keep documentation.
3. Self-employment and Schedule C losses
Self-employed filers see higher audit rates because there is more room for error and underreporting. Repeated business losses, especially in activities that look like hobbies, are a classic flag.
4. Home office and vehicle deductions
Claiming 100% business use of a vehicle or an oversized home office raises eyebrows. These are legitimate deductions, but they require honest, well-documented calculations.
5. Cash-heavy businesses
Restaurants, salons, and other cash businesses receive extra attention because cash income is easy to underreport. Clean books are your best defense.
Documentation beats everything
Most audits are won or lost on records. Keep receipts, mileage logs, and bank statements for at least three years — the standard IRS audit window — and longer for substantial items.
6. Round numbers everywhere
Returns full of suspiciously round numbers ($5,000 here, $10,000 there) suggest estimates rather than records. Report actual figures.
7. Claiming the wrong credits
Refundable credits like the Earned Income Tax Credit are audited more often because of high error rates. Make sure you genuinely qualify and can prove dependents and residency.
8. Foreign accounts and crypto
Unreported foreign accounts (FBAR/FATCA) and digital-asset transactions are enforcement priorities. The return now asks directly about digital assets — answer it accurately.
9. Math errors and mismatched returns
Simple math mistakes and information that does not match IRS records can generate notices and, sometimes, deeper review. E-filing with good software reduces this risk.
What to do if you're audited
First, do not panic and do not call the auditor casually — you have the right to professional representation under the Taxpayer Bill of Rights. A representative responds on your behalf, provides only what is requested, and keeps the audit from expanding. If you disagree with the result, you can appeal.
Audited or worried you might be? Talk to us.
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Start Your Free ConsultationThe takeaway
You cannot eliminate audit risk entirely, but accurate reporting and good records make most audits routine and winnable. And if an audit turns into a balance you cannot pay, the same resolution options for back taxes apply.
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About the author
This article was written by the certified tax team at US Certified Tax Services — IRS enrolled agents and tax professionals who resolve federal and state tax debt every day. It is general information, not legal or tax advice. For guidance on your specific situation, request a free consultation.