The IRS requires a contemporaneous log for mileage deductions. That means recording trips when they happen, not reconstructing them at year end from memory. Your log needs the date, destination, business purpose, and miles driven for each trip. “Various client visits” covering three months won’t hold up in an audit.

The easiest way to track is a mileage app. MileIQ, Stride, Everlance, and others run in the background on your phone and automatically detect trips. You swipe to classify each trip as business or personal. At year end, you export a report showing every business mile with dates and destinations. The annual cost is minimal compared to the deduction it protects.

If you prefer manual tracking, keep a notebook in your vehicle. Write down odometer readings at the start and end of each business trip. Note where you went and why. Update it immediately, not three days later when you’ve forgotten the details.

Trades professionals who work at different locations daily can deduct trips from home to each job site since they don’t have a fixed office. But regular commuting doesn’t count. Driving from home to your usual place of business is personal mileage, not deductible.

The IRS offers two methods for calculating the deduction. The standard mileage rate is updated annually and you simply multiply your business miles by that rate. The actual expense method means deducting the business percentage of all vehicle costs including gas, insurance, repairs, and depreciation. Actual expenses requires more recordkeeping but often yields larger deductions for trucks with high maintenance costs. You have to choose the standard mileage rate in the first year you use a vehicle for business if you want that option at all.

Separate vehicles help if you can manage it. A truck used 95% for business means nearly all expenses and mileage are deductible with minimal allocation questions. A personal car used 40% for business means splitting every expense and defending that percentage if audited.

The mistake most business owners make is not tracking consistently. You remember the long drive to that one client three hours away but forget the dozens of shorter trips to the supply house, bank, and post office. Those short trips add up fast. Someone making ten trips a week averaging 15 miles each racks up 7,800 business miles per year. At current rates, that’s thousands in deductions you’d lose without documentation.

Working with a Metro Detroit bookkeeping service means someone reviews your expense tracking and catches gaps before tax time. If you’ve been estimating mileage or guessing at percentages, you’re probably leaving money on the table or creating audit risk.