Choosing a method
The method that yields a larger deduction depends on annual miles, fuel/maintenance costs, and vehicle type. You generally choose a method the first year a vehicle is placed in service.
Standard mileage method
Multiply business miles by the IRS rate for the year. Add parking and tolls. Keep a log showing date, destination, purpose, and miles.
Actual‑expense method
Track fuel, insurance, repairs, lease or depreciation, and allocate by business‑use percentage. Keep all invoices and a mileage log to compute the percentage.
Mileage logs & substantiation
Maintain contemporaneous logs—apps, GPS, or paper—to support your deduction. Reconstructing after year‑end is risky.