Annual Percentage Rate—or APR—is the yearly cost of borrowing money, shown as a percentage. When you take out a loan, use a credit card, or finance a purchase, lenders quote you an APR. Understanding what that number actually means helps you compare offers fairly and spot the real cost hiding behind different loan terms.

The articles here answer questions like: How does APR differ from interest rate? Why do credit cards show different APRs for different types of transactions? What does it mean when a loan has a variable APR? And how do you use APR to figure out which borrowing option costs you less money over time?