Business Deductions: Home Office, Vehicles, and Commonly Missed Expenses

Many first-time business owners miss significant deductions like home office, vehicle expenses, and startup costs. Proper documentation and strategic timing ensure you claim every legitimate deduction while remaining audit-defensible.

Home office is often the biggest missed deduction. The regular method (Form 8829) lets you deduct a proportionate share of mortgage interest, property tax, utilities, insurance, repairs, and depreciation based on the square footage used exclusively for business. The simplified method caps at $1,500 (300 sq ft at $5/sq ft). For most home-based businesses, the regular method produces a larger deduction.

Vehicle expenses offer two methods. The standard mileage rate (67 cents per mile for 2024) is simple to track. The actual expense method deducts gas, insurance, maintenance, depreciation, and lease payments based on business-use percentage. You must choose the standard rate in the first year you use the vehicle for business if you want to use it later.

Startup costs get special treatment. Under Section 195, you can deduct up to $5,000 in startup costs in your first year, with the remainder amortized over 180 months. The $5,000 deduction phases out dollar-for-dollar when total startup costs exceed $50,000.

Other commonly missed deductions. Self-employed health insurance premiums (100% deductible above the line), retirement plan contributions, continuing education, professional subscriptions, and business insurance.

The pitfall: Aggressive deductions without proper documentation invite audit scrutiny. A CPA ensures each deduction is substantiated and defensible under IRS rules.