The deductibility of credit card interest depends on the purpose of the underlying purchases. Interest on trade or business expenses is deductible while interest on personal expenses is not. The type of credit card used doesn't matter. Interest on a personal credit card can be deducted if used for a business expense. Conversely, interest on a business credit card doesn't qualify for a deduction if used for personal expenses.Self-employed individuals and independent contractors can deduct credit card interest on their trade or business expenses even if they don't have a separate business entity.