Short answer
A debit card spends money directly from your own bank account, while a credit card lets you borrow money from the card issuer, which you repay later — potentially with interest.
Both look and function similarly for everyday purchases, but the underlying money is fundamentally different.
Debit card
- Draws directly from your checking or savings account balance
- You can't spend more than what's actually in your account (barring overdraft features)
- No interest charges, since you're not borrowing
Credit card
- Lets you borrow up to a set credit limit from the issuer
- You repay the borrowed amount later, usually monthly
- If not paid in full by the due date, the remaining balance accrues interest, often at a high rate
- Responsible use can help build a credit history and credit score, which debit cards generally don't affect