Personal interest is not deductible. Personal interest is any interest that is not home mortgage interest, investment interest, business interest, or other deductible interest.

Per IRS Publication 17 Your Federal Income Tax (For Individuals), page 175:

Personal Interest

Personal interest isn't deductible. Personal interest is any interest that isn't home mortgage interest, investment interest, business interest, or other deductible interest. It includes the following items.

• Interest on car loans (unless you use the car for business).
• Interest on federal, state, or local income tax.
• Finance charges on credit cards, retail installment contracts, and revolving charge accounts incurred for personal expenses.
• Late payment charges by a public utility.

TIP: You may be able to deduct interest you pay on a qualified student loan. For details, see Publication 970, Tax Benefits for Education.