Yes, you should divide the vehicle expenses in half if you use your vehicle 50/50 for each business. You can also use any other appropriate percentage rate.
You can only deduct mileage if you keep a written log of your
miles otherwise you can't deduct mileage. Per
IRS, you have to have adequate evidence. See https://www.irs.gov/publications/p463/ch05.html .
The IRS considers adequate evidence as a log of "who,
what, when, and where" which
may include the following:
- The
cost of the car and any improvements,
- The
date you started using it for business,
- The
mileage for each business use,
- The
total miles for the year.
- Date
of the expense.
- Your
business destination.
- Business
purpose for the expense.
If you are
self-employed (Schedule C), enter/edit your vehicle's mileage:
- Log
on to TurboTax and click on the orange button, Take me to my return.
- Type vehicle expenses, self-employed
business in the search/find box and click search.
- Click on Jump to vehicle
expenses, self-employed business.
- Edit your business.
- At the 'Your xxxx Business' screen,
scroll down to Business Expenses.
- Click start/update next to Business
Vehicle Expense.
- Continue with the onscreen interview until you
get to the 'How Do You Want to Enter Your Mileage for your vehicle'.
See the screenshot below.
