It’s a prediction of how likely you are to repay borrowed money on time. It comes entirely from the information in your credit reports. It’s not a measure of your income, your savings, or your overall wealth. Instead, it focuses narrowly on your history of borrowing and repaying. Most widely used credit scores, including FICO scores, range from 300 to 850, with higher scores generally signaling lower risk to a lender.

You don’t have just one credit score. Different scoring models, different credit bureaus, and even different points in time can all produce slightly different numbers for the same person. That’s why the score a lender pulls might not exactly match a score you saw somewhere else.

FICO, the most widely used scoring model, has disclosed the general categories that go into its calculation, along with their approximate weight. Payment history carries the most weight, around 35%. It reflects whether you’ve paid bills on time or missed payments, had accounts go to collections, or filed for bankruptcy. Amounts owed comes next, around 30%, which largely reflects your credit utilization: how much of your available credit you’re actually using.

Length of credit history accounts for roughly 15%, rewarding accounts that have been open and in good standing for a longer time. New credit makes up about 10%, reflecting recently opened accounts and recent credit inquiries. Credit mix accounts for the final 10%. It reflects whether you have experience managing different types of credit, like a mix of credit cards and installment loans, rather than only one type.

These weights are approximate and can shift slightly between different FICO score versions. Other scoring models, like VantageScore, use a somewhat different weighting scheme entirely. Even so, the same broad categories (payment history and credit usage chief among them) tend to dominate across nearly every model in use.

Credit utilization (the percentage of your available revolving credit currently in use) is one of the more heavily weighted individual factors within the “amounts owed” category. A cardholder with a $10,000 total credit limit carrying a $2,000 balance has a 20% utilization ratio. The same $2,000 balance on a $4,000 limit produces a 50% utilization ratio, a meaningfully worse signal, even though the dollar amount owed is identical.

This is why paying down balances, or requesting a credit limit increase without adding new spending, can improve a score relatively quickly. Compare that to a factor like length of credit history, which can only improve gradually over time, no matter what action you take. Card issuers typically calculate utilization both per card and across all your revolving accounts combined. So a single maxed-out card can drag down your overall utilization ratio, even if your other cards carry low balances.

A credit report and a credit score are related but different things. Credit bureaus like Equifax, Experian, and TransUnion maintain your credit report: a detailed record of your credit accounts, payment history, and inquiries. A formula calculates your credit score from the information in that report. Errors on your credit report (an account that isn’t actually yours, an incorrect late payment) can unnecessarily drag your score down. That’s why checking your credit report periodically for accuracy matters as much as monitoring the score itself.

You’re entitled to a free copy of your credit report from each of the three major bureaus, on a regular basis, through AnnualCreditReport.com. It’s the only source federal law authorizes to provide these free reports. Disputing a genuine error is a formal process. You handle it directly with the credit bureau reporting the inaccurate information. Bureaus must investigate disputes within a set timeframe, once you file them.

Lenders use credit scores to decide whether to approve a mortgage, auto loan, or credit card application, and the specific interest rate or credit limit offered. Beyond traditional lending, landlords often check credit as part of a rental application. Some insurance companies also use credit-based information to help set premiums, sometimes called an insurance score. That draws on similar underlying data, but isn’t identical to a standard credit score.

Even employers sometimes review a modified version of a credit report, though not a numeric score, as part of a background check for certain positions, particularly roles involving financial responsibility. Federal law restricts this use more than lending decisions, though, and typically requires your explicit consent.

FICO has never disclosed its exact scoring algorithm, only the general categories and their approximate weights. This means no one, not even financial advisors, can tell you with certainty exactly how many points a specific action will add or subtract from your score. But FICO’s own disclosures, and broad patterns observed across scoring models, do make one thing clear: which general behaviors tend to help, and which tend to hurt. That holds even without an exact point value attached to each one.

This uncertainty is part of why generic advice like “pay your bills on time” and “keep balances low” tends to work reliably across virtually every scoring model, even without an exact formula. Those behaviors sit inside the two most heavily weighted categories, regardless of the specific model’s undisclosed internal math.

Your credit score directly affects the interest rates lenders offer you on loans and credit cards. That, in turn, affects your actual monthly payments and total interest costs. Our Credit Card Payoff Calculator and APR Calculator can help you see how a given rate translates into real dollar costs, whatever your current credit profile looks like.