IRS Audit Triggers: 10 Red Flags That Increase Your Risk

IRS Audit Triggers: 10 Red Flags That Increase Your Risk

The IRS audits less than 1% of all returns annually, but certain patterns significantly increase your odds of scrutiny. Understanding what draws attention helps you file accurately, document thoroughly, and make informed decisions about deduction claims.

How the IRS Selects Returns for Audit

The IRS uses a scoring system called the Discriminant Index Function (DIF) to identify returns with the highest potential for additional taxes. Returns scoring above a threshold are reviewed by an agent. Common additional selection criteria include:

• Computer-matching programs comparing your return to information reports (W-2s, 1099s, K-1s)
• Random selection as part of the National Research Program
• Related examinations (your business partner was audited)
• Whistleblower referrals

10 Audit Red Flags

1. Not Reporting All Income

The IRS receives copies of every W-2, 1099-NEC, 1099-MISC, 1099-B, and 1099-INT issued to you. If your return does not match those information returns, the computer flags it automatically. Report all income — including 1099-K payments, gig work, and crypto transactions.

2. Large Charitable Deduction Relative to Income

Donating 20-30% of your income to charity is statistically rare and draws attention. The IRS has published norms for charitable giving by income level. Exceeding those norms requires solid documentation: written acknowledgments from charities for donations over $250, Form 8283 for non-cash donations over $500.

3. Claiming 100% Business Use of a Vehicle

Claiming that a personal vehicle is used 100% for business is a common audit trigger. The IRS knows most people use their car for personal trips. The standard mileage log requirement exists for exactly this reason. If you have a second personal vehicle or the vehicle is inherently business-use (a delivery van with your company logo), 100% use may be defensible — but document it thoroughly.

4. Large Home Office Deduction

A home office deduction is legitimate and not automatically suspicious. What raises flags is a deduction that is disproportionately large relative to your business income or a space that clearly fails the regular and exclusive use test.

5. Schedule C Losses Year After Year

A business that consistently generates losses may be classified as a hobby by the IRS (under the hobby loss rules, losses from activities without a profit motive are not deductible). The IRS generally presumes a profit motive if the business was profitable in at least 3 of the last 5 years.

6. Round Number Deductions

Real business expenses rarely come out to exactly $10,000 or $5,000. Returns with suspiciously round numbers suggest estimation rather than actual tracking. Keep receipts and report actual amounts.

7. High Meal and Entertainment Deductions

Meal deductions must have a clear business purpose and attendees documented. Claims that represent an unusually high percentage of business income draw scrutiny.

8. Cash-Intensive Businesses

Restaurants, hair salons, car washes, and other cash-heavy businesses are statistically audited more frequently because underreporting cash income is common. Reported revenue that seems low for your industry and location raises flags.

9. Cryptocurrency Transactions

The IRS requires reporting all crypto gains and losses. With exchange 1099s now mandatory, unreported crypto transactions are automatically flagged. Every swap, sale, or use of crypto to purchase goods is a taxable event.

10. Claiming Earned Income Tax Credit with High Income

The EITC has strict income requirements. If there are discrepancies between reported income and the credit claimed — or if dependents are claimed by multiple taxpayers — the IRS computer flags the return.

If You Are Audited: What to Know

Most IRS audits are correspondence audits — the IRS sends a letter asking you to verify specific items. You respond by mail with documentation.

Keep these records for at least 3 years from the filing date (6 years if you underreported income by more than 25%, indefinitely for unfiled returns).