Your credit score is a three-digit number, typically between 300 and 850, calculated from your credit history to predict how likely you are to repay money you borrow. It works by running the data in your credit report through a scoring formula that weighs five factors unequally, and it matters because lenders, landlords, and sometimes employers use that single number to judge you before they ever read the full report behind it.
Where the number actually comes from
The score is not pulled from thin air. It is calculated from the credit report maintained by one of three major credit bureaus, Equifax, Experian, and TransUnion, each of which independently tracks your borrowing and repayment activity as reported by lenders. Because each bureau can hold slightly different information, the same person can have three somewhat different scores at any given time, depending on which bureau’s data was used. The most widely used scoring model built on top of that data is the FICO Score, developed by the Fair Isaac Corporation; VantageScore is a common alternative that uses a similar approach with its own formula.
The five ingredients, and how much each one counts
According to myFICO, the company’s formula weighs five categories unevenly rather than treating them as equal parts of a total. Payment history carries the most weight at 35%, reflecting whether you have paid past credit accounts on time, since a missed payment is the clearest signal of repayment risk a lender has, and its heavy weighting is why a single late payment can do more damage to a score than almost any other single event. Amounts owed follows at 30%, driven largely by credit utilization, the share of your available credit you are actually using at any given time. Length of credit history accounts for 15%, rewarding accounts that have stayed open and in good standing longer. New credit makes up 10%, capturing recent applications and newly opened accounts, since a burst of new borrowing can itself look risky. Credit mix, the variety of account types you manage, such as credit cards, auto loans, and mortgages, rounds out the final 10%.
Why utilization deserves special attention
Because amounts owed is the second-largest factor, credit utilization is worth isolating. It is the percentage of your available credit that you are currently using across all accounts combined, and running that number high, even if you pay the bill in full every month, can drag your score down, because scoring models read a high balance relative to your limit as a sign of financial strain regardless of whether you eventually pay it off. Keeping balances low relative to credit limits, and paying on time every cycle, are the two most reliable levers most people actually have over their own score, since together payment history and utilization account for 65% of the formula, far more than the other three categories combined.
Why the number matters beyond the number itself
A higher credit score generally translates into lower interest rates and better terms on loans, credit cards, and, in some states, insurance premiums, which can add up to real savings over the life of a loan. Because the score comes directly from the report, an error on that report, an account that isn’t yours, a payment wrongly marked late, can drag the score down through no fault of the consumer. The Consumer Financial Protection Bureau notes that people are entitled to free copies of their credit reports, which makes it possible to check the underlying data behind the score and dispute mistakes before they cost you a better rate on the next loan or lease application.