While my work vehicle was being repaired I rented a vehicle for work. Do I count those miles for deductions or do I deduct the cost of the rental?

[Carl]

No, you can not take the per-mile deduction on a rented vehicle that you do not own. You can only claim the rental expense. There's a place in the business expenses section where you report rents paid for anything and everything your business paid rent for.

[MinhT1]

If you're self-employed and the rental car was used for your business, you can deduct the cost of the rental as a business expense.