What is Deductible "Business" Mileage?
Your "business" mileage is the mileage you drive for your business, but does not include the commuting mileage used to drive to your main business location.
If you work out of your home, and qualify to deduct expenses for business use of your home, travel from your home to a customer or other business location is NOT commuting, but deductible business
If you are not permitted to claim a business deduction for your home as your principal place of business, your mileage to your office, shop, etc. would be non-deductible commuting. However, travel from there to other temporary business locations would generally be considered business mileage.
If you have several places of business you might visit in the same day, travel from your home to the first place, and travel from the last place to your home at the end of the work day, would be considered your non-deductible commute. Your mileage in between the locations during the day is considered business mileage.
Example: Dr. Jones works at three hospitals, West, Central and East, which are on the same road 5, 15 and 40 miles away from his home, respectively. If he visits them in that order, the distance between West and Central (10) and Central to East (25) is deductible business mileage, and his commute to West (5) and back from East (40) is non-deductible commuting. However, if he simply visits East before Central, his total deductible business mileage goes up from 35 miles to 60 miles!
Travel out of your metropolitan area to a temporary business location, where you need to stay overnight, is business mileage.