Interest is the cost of borrowing money or the reward for lending it. When you borrow through a loan or credit card, you pay interest to the lender. When you deposit money in a savings account or buy a bond, you earn interest on your balance. Understanding how interest rates work—and how they're calculated—shapes every major financial decision, from choosing where to save to comparing loan offers.
The articles here explain how interest compounds over time, why different accounts and investments offer different rates, and how to read the terms lenders and banks use. You'll learn the difference between simple and compound interest, how annual percentage rates compare across products, and what factors affect the rates you're offered.