Taxes
10 Schedule C mistakes that cost 1099 contractors thousands
From skipping the mileage deduction to mixing personal expenses, these are the most common Schedule C mistakes — and how to avoid them.
By MileTracker · April 4, 2026 · 9 min read
Schedule C looks simple — one page, a short list of expenses. The mistakes are subtle, and they're expensive. Here are 10 to avoid.
1. Not deducting mileage
The most common, most expensive mistake. Use a tracker.
2. Forgetting Part IV
If you claim vehicle expenses, you must complete Part IV. Skipping it is an audit flag.
3. Claiming commute as business
Don't. The IRS will disallow it.
4. Mixing personal and business expenses
Use a separate bank account and credit card for business.
5. Skipping home office
If you qualify, take it. The simplified method is easy.
6. Forgetting health insurance
Self-employed health insurance is deductible above the line.
7. Missing retirement contributions
SEP-IRA contributions can be huge.
8. Forgetting QBI
The 20% QBI deduction is automatic but easy to miss without a tax pro.
9. Bad recordkeeping
Receipts, mileage log, mileage purpose. Keep everything.
10. Filing late
File on time or extend. Penalties are real.
MileTracker detects every drive in the background, lets you classify business or personal in one tap, and exports an IRS-ready PDF and CSV at tax time. Download MileTracker free on the App Store.