What Are IRS Audit Red Flags?

There’s no single item on a tax return that guarantees an audit, but certain patterns raise your DIF score significantly and draw IRS attention at a rate well above average.

The IRS doesn’t audit randomly — it audits when its statistical models predict a return is likely to generate additional tax if examined. That means the red flags worth paying attention to are the ones that produce statistical outliers: deductions that are large relative to your income, income that doesn’t match information returns, and transactions in categories the IRS already knows are frequently misreported. Below is a specific rundown of what actually moves the needle.

Schedule C Losses, Especially Repeated Ones

A Schedule C sole proprietorship that reports losses year after year is one of the most consistently scrutinized patterns in the individual return audit selection process.

The IRS applies the hobby loss rules under IRC § 183 to businesses that fail to show a profit in at least three of the last five tax years. If your activity looks more like a personal interest than a bona fide business — and the returns back that up — the IRS can disallow the losses and recharacterize the activity as a hobby, eliminating the deduction entirely.

Cash-intensive businesses — restaurants, contractors, car washes, salons — are also audited at disproportionately high rates because the IRS knows cash transactions are difficult to verify and frequently underreported. An examiner on a cash business audit will compare your reported gross receipts against your bank deposits, markup ratios, and supplier invoices. Unexplained discrepancies become proposed adjustments.

Large Charitable Deductions Relative to Income

Charitable deductions that are unusually large relative to your income level are a known DIF score driver — and the documentation requirements are strict.

Noncash contributions over $500 require Form 8283. Contributions of property valued above $5,000 require a qualified appraisal from a certified appraiser, completed before the tax return due date. Inflated clothing donations and vehicle contributions where the claimed value far exceeds what a charity actually received are a recurring IRS target — the IRS has matched donor-claimed values against the Form 1098-C acknowledgments filed by charities and found the gaps.

The deduction itself isn’t a problem. The problem is claiming $40,000 in charitable deductions on a $120,000 adjusted gross income without the paperwork to back it up. Keep written acknowledgments for every contribution over $250, maintain qualified appraisals for property donations, and make sure the values on Form 8283 match what the donee organization can confirm.

Home Office Deductions

Home office deductions are legitimate for self-employed taxpayers whose qualifying workspace meets the IRC § 280A standard — but they’re among the most commonly disallowed deductions the IRS sees.

Under the Tax Cuts and Jobs Act (2018), employees can no longer deduct home office expenses as miscellaneous itemized deductions. That deduction is gone until 2025 at the earliest under current law. Self-employed taxpayers can still claim the home office deduction, but only for space used regularly and exclusively for business. ‘Regularly and exclusively’ is the key — a guest room that doubles as an office, or a dining table where you sometimes work, doesn’t qualify.

The IRS looks at the size of the deduction relative to total home expenses, whether the claimed square footage is plausible, and whether the filer’s income and business activity are consistent with the home office claim. Sole proprietors with home office deductions that represent an unusually high percentage of their gross income tend to score higher on the DIF.

Unreported or Underreported Income

The IRS’s Automated Underreporter (AUR) program cross-references every return against third-party information returns — and mismatches generate a CP2000 notice.

Digital assets have been on the IRS’s radar since before the checkbox appeared on Form 1040 in 2019. Every year the IRS asks: ‘At any time during [year], did you receive, sell, exchange, or otherwise dispose of any digital assets?’ Answering no when you had reportable transactions is a known compliance issue, and Form 1099-DA — the new broker reporting form for digital asset transactions — went into effect for tax year 2025. Reporting gaps are getting harder to maintain as broker reporting expands.

For cash-intensive businesses, the IRS uses bank deposit analysis to test reported gross receipts: total deposits plus cash spent directly without being deposited should approximate your gross income. Unexplained deposits, regular large cash transactions, or deposits that consistently exceed reported income are patterns examiners are specifically trained to look for.

High Travel, Meals, and Entertainment

Post-TCJA, entertainment expenses are entirely non-deductible under IRC § 274, and meals are only 50% deductible — but many returns still reflect pre-2018 treatment.

The IRS looks for businesses where travel, meals, and entertainment expenses are disproportionately large relative to gross receipts, or where the expense categories don’t match the nature of the business. A solo consultant with $80,000 in revenue claiming $25,000 in meals and travel is a statistical outlier. An examiner will ask for receipts, business purpose documentation, and records of who was present — the contemporaneous recordkeeping requirement under IRC § 274(d) is strictly enforced.

The practical issue here is that many business owners run genuinely deductible expenses through these categories alongside personal expenses that shouldn’t be there. The IRS doesn’t need to prove that all of it is personal — finding even a few disallowable items gives the examiner grounds to expand the inquiry.

Foreign Bank Accounts

Taxpayers with foreign financial accounts exceeding $10,000 in aggregate value at any point during the year are required to file an FBAR (FinCEN Form 114) — separate from and in addition to their federal tax return.

The FBAR is not a tax document; it’s filed with FinCEN, not the IRS. But non-compliance is treated as a serious enforcement priority. Penalties for non-willful FBAR violations can reach $10,000 per account per year. Willful violations carry penalties up to the greater of $100,000 or 50% of the account balance per violation — and can include criminal referral.

FATCA (IRC § 6038D) imposes a separate disclosure requirement on Form 8938 for taxpayers with foreign financial assets above reporting thresholds ($50,000 single filer, $100,000 joint). Both the FBAR and Form 8938 are required for taxpayers who meet the thresholds — they’re not duplicative, they’re parallel obligations. If you have foreign accounts and haven’t been filing both, the IRS has programs for coming into compliance before you’re contacted.

Real Estate Losses Above the Passive Activity Limits

Rental real estate losses are subject to the passive activity loss rules under IRC § 469, which limit most taxpayers to a $25,000 annual deduction — and that allowance phases out completely at $150,000 in adjusted gross income.

Taxpayers who claim unlimited real estate losses on the theory that they qualify as ‘real estate professionals’ under IRC § 469(c)(7) are a known IRS audit target. The real estate professional exception requires that more than 50% of your personal services during the year were in real property trades or businesses, and that you materially participated in those activities for more than 750 hours. The IRS looks for contemporaneous time logs, and the absence of them is often fatal to the claim.

If you’re a high-income W-2 earner with a few rental properties claiming large losses on the real estate professional exception, that’s a combination the IRS’s statistical models are specifically calibrated to flag.

High Income Generally

Returns above $1 million in adjusted gross income are audited at a rate roughly five to ten times higher than average returns — not because high earners cheat more, but because the dollar yield per audit is higher.

IRS audit rates drop sharply at middle-income levels and rise sharply at the top. The agency allocates examination resources based on expected return per case, and a high-income return with a complex deduction profile simply offers more potential revenue than a straightforward W-2 return. If you’re above the $1 million threshold, the elevated audit rate is a structural feature of being at that income level, not a signal that your return has a specific problem.

Frequently Asked Questions

What are the biggest IRS audit red flags?

The patterns most consistently associated with elevated audit risk are: repeated Schedule C losses or hobby-loss situations; large charitable deductions without proper documentation; home office deductions claimed on returns where the space doesn’t qualify; unreported digital asset transactions; high travel and meals expenses relative to revenue; undisclosed foreign bank accounts; and real estate losses claimed under the professional exception without the hours to support it.

Does claiming a home office increase your chances of an IRS audit?

A legitimate home office deduction — exclusive and regular business use, properly calculated — should not be avoided out of audit fear. What increases audit risk is a home office deduction that looks disproportionate relative to your income or the nature of your business, or one where the space doesn’t actually meet the IRC § 280A standard. Document it correctly and the deduction is defensible.

Do large charitable deductions trigger audits?

They can increase your DIF score, particularly if the deduction is large relative to your income. The IRS has also matched donor-claimed values against charity-reported values and found consistent inflation in clothing and vehicle donations. The deduction itself is legitimate — the issue is documentation. Form 8283 is required for noncash donations over $500, and a qualified appraisal is required for donations of property over $5,000.

Does the IRS audit high-income taxpayers more often?

Yes, meaningfully so. IRS data consistently shows audit rates for returns above $1 million are five to ten times higher than for average returns. The audit rate for middle-income W-2 earners is quite low. The elevated rate at high income is driven by expected dollar yield per examination, not by assumption of wrongdoing.

If your return has been selected for examination — or you’ve received a notice and want to understand your exposure — our IRS audit defense page covers the process from initial notice through resolution. For a full breakdown of how IRS audits work at each level, read our complete guide to IRS audits. To talk through your specific situation, book a free 15-minute call.