What expense deductions trigger IRS audits for gig workers?

No single deduction guarantees an audit, but a handful of Schedule C expense patterns reliably draw IRS attention: claiming 100% business use of a vehicle, an outsized home office, deductions that are disproportionately large relative to your reported income, and a business that keeps reporting losses (the "hobby loss" trap). None of these is illegal if it's true — the risk comes from claiming them without the records to back them up.

The good news: the overall individual audit rate is low, and the fix for every red flag below is the same — claim only what you actually spent on the business, and keep contemporaneous records. The IRS is explicit that the burden of proof is on you: "You must be able to prove certain elements of expenses to deduct them."

The four red flags

100% vehicle use. Per Kiplinger, "claiming 100% business use of an automobile is red meat for IRS agents" — examiners know it's rare to use a car purely for work with no personal driving, especially when you own no other vehicle. A tax-resolution overview frames it the same way: it's "extremely rare that any self-employed individual will use their vehicle strictly for business and no personal use." If you take the standard mileage rate, the IRS still requires you to substantiate your expenses "by adequate records or by sufficient evidence."

A large home office. The deduction is legitimate, but it's "often subject to scrutiny by the IRS due to the potential for abuse or misinterpretation of the rules." It's only valid if the space is used regularly and exclusively for business. The simplified method lets you deduct $5 per square foot up to 300 square feet — a $1,500 cap — and keeps the math conservative. Claiming a large share of your home as office space against modest income invites questions.

Disproportionately large deductions. The IRS "closely scrutinizes deductions, particularly those that seem disproportionate to your reported income or industry norms." Returns that fall far outside the norm for your earnings and trade are statistically more likely to be flagged.

The hobby-loss trap. Reporting losses "year after year can be perceived as an attempt to artificially reduce taxable income." Under the nine-factor profit-motive test in Reg. 1.183-2(b), the IRS weighs how businesslike your records are, your expertise, and your profit history. As the Journal of Accountancy explains, Sec. 183(d) presumes a profit motive "if an activity has gross income for three or more of the last five years that exceeds the deductions attributable to the activity" — fall short and the burden shifts to you.

How to stay clean

Deduct only your real business share — split mixed-use costs honestly and never round vehicle use up to 100%. Keep a contemporaneous mileage log and receipts as you go, not the night before an audit. Use the simplified home-office method if your space is small, and confirm it's used exclusively for work. Run your gig like a business: separate bank account, organized books, and a genuine profit motive. See our home office deduction rules and vehicle mileage guides for the specifics, and our audit-protection overview if you want a specialist in your corner.

Sources

• IRS — Recordkeeping (burden of proof)
• IRS — Simplified option for the home office deduction
• IRS — Topic No. 510, Business use of car
• Kiplinger — Ten IRS Audit Red Flags for Self-Employed Individuals
• Tax Defense Network — 7 Common Audit Red Flags for the Self-Employed
• Journal of Accountancy — Business or hobby? The nine factors