Credit Scores: The Number That Sets Your Interest Rate

Credit is simply borrowing money now with a promise to repay it later — a credit card, a car loan, or a mortgage all count. Every time you borrow and repay, you build a track record. Lenders use that record to guess one thing: how likely are you to pay them back? Recall from earlier cards that interest is the price of borrowing — credit history is what determines how high that price will be for you.

That track record gets summarized into a credit score, a number that in the most common U.S. model (FICO) ranges from 300 to 850. Higher is better. The score is built mostly from your payment history (do you pay on time? ~35% of a FICO score) and amounts owed (how much of your available credit you're using, ~30%). The rest comes from the length of your history, your mix of credit types, and how much new credit you've recently opened.

Why does this matter so much? Because the score directly shapes the cost of borrowing. Imagine two people each take a $20,000 car loan. Someone with an excellent score might get 6% interest, while someone with a poor score might pay 13% — a difference of thousands of dollars over the loan. A good score also decides whether you're approved at all.

The encouraging part: a score isn't fixed. Paying bills on time and keeping balances low relative to your limit are the two biggest levers, and they compound in your favor over years.