What Is a Credit Score? How It Works and What Affects It

A credit score is a three-digit number that summarizes how risky you look to a lender, based on the information in your credit reports. The Consumer Financial Protection Bureau describes it as a prediction of your credit behavior — most specifically, how likely you are to repay a loan on time.

That single number, generally somewhere between 300 and 850, influences whether you get approved for a credit card, mortgage, or auto loan, and what interest rate you're offered if you do.

Where the Number Comes From

Your credit score isn't stored anywhere by itself — it's calculated, on demand, from the data in your credit reports. Three nationwide credit reporting agencies — Equifax, Experian, and TransUnion — each maintain their own file on you, built from information reported by lenders, credit card issuers, and sometimes collection agencies. A scoring model then runs that data through a formula to produce a number.

Because each bureau's file can differ slightly (not every lender reports to all three), and because there's more than one scoring model in use, you don't actually have just one credit score — you have several, and they can differ from each other.

The Two Major Scoring Models

The two models behind nearly every credit score in the U.S. are FICO and VantageScore. Both use the same 300–850 range and pull from the same underlying bureau data, but they weigh that data somewhat differently, which is why your FICO score and your VantageScore can land in different places even on the same day.

FICO has historically been the model most widely used in mortgage underwriting specifically. VantageScore, developed jointly by the three bureaus, is commonly used for many of the free scores offered by banks and credit card apps, and it's designed to score some consumers with thinner or shorter credit histories that older FICO models couldn't.

Neither model is the "real" one — both are legitimate, widely used measures, just calibrated differently. If you're checking your score before a specific application, it's worth knowing which model that lender is likely to pull, since the free score in your banking app may not match it exactly.

What Actually Goes Into the Score

Both major models draw on the same broad categories of information, even though the exact weighting differs between them:

Payment history — whether you've paid past accounts on time — is generally the single largest factor in both models. Late payments, collections, and bankruptcies weigh heavily here.

Amounts owed / credit utilization — how much of your available credit you're currently using — is typically the second-largest factor. Carrying a high balance relative to your credit limits tends to lower your score, even if you pay it off in full every month, because scoring models often look at whatever balance is reported at a given point in time.

Length of credit history — how long your accounts have been open, including the age of your oldest and newest accounts — rewards a longer track record.

Credit mix — whether you have experience managing different types of credit, such as revolving credit cards and installment loans — plays a smaller role.

New credit — how many new accounts you've opened recently, and how many hard inquiries have hit your report — also factors in, since opening several accounts in a short window can look riskier.

Income, employment status, and net worth are not part of any standard credit score calculation. It's entirely possible for someone with a modest income to have an excellent score, and for a high earner to have a poor one, based purely on borrowing and repayment behavior.

Soft Inquiries vs. Hard Inquiries

Not every credit check affects your score. A soft inquiry happens when you check your own credit, or when a company pre-screens you for an offer without a full application — these don't affect your score at all. A hard inquiry happens when you actually apply for credit and authorize a lender to pull your full report for a lending decision, and this type can cause a small, typically temporary dip.

Checking your own credit report or score, no matter how often, is always a soft inquiry.

Your Right to Free Credit Reports

Under the Fair Credit Reporting Act, you're entitled to a free copy of your credit report from each of the three nationwide bureaus. Since a program first introduced during the COVID-19 pandemic was made permanent in 2023, that free access is now available weekly, not just once a year, through the single federally authorized source: AnnualCreditReport.com. Other sites advertising "free" credit reports may not be the same authorized service, so that's the one address worth using directly.

Checking your credit report is a different thing from checking your credit score — the report is the underlying record of accounts, balances, and payment history; the score is the number calculated from it. Reviewing the report periodically is also how you catch errors, such as an account that isn't yours, before they drag your score down.

Why the Number Matters

Lenders use credit scores to decide both whether to extend credit and what to charge for it. A stronger score generally means access to lower interest rates and better terms across mortgages, auto loans, and credit cards, while a weaker score can mean higher rates, larger required down payments, or outright denial.

Beyond lending, some landlords, insurers, and utility providers may also use credit information as part of their own decision-making, depending on state law and their own policies.

Frequently Asked Questions

What's a "good" credit score?

Both major scoring models generally consider scores in the high 600s and above to be solidly good, with the specific cutoffs differing slightly between FICO and VantageScore. Rather than memorizing a single universal number, it's more useful to know that higher generally unlocks better terms, and that lenders often reserve their very best rates for scores well above the "good" threshold.

Does checking my own credit score lower it?

No. Checking your own score or report is always a soft inquiry, which has no effect on your score, regardless of how often you check.

Why do I have different scores from different apps?

Different credit-monitoring tools and lenders may use different scoring models (FICO vs. VantageScore), pull from different bureaus, or use different score "versions." Seeing several different numbers for yourself is normal, not a sign something is wrong.

Does my income affect my credit score?

No. Standard credit scoring models don't factor in income, employment, or net worth — only your credit-related borrowing and repayment behavior.

How often does my credit score update?

It can change whenever a lender reports new information to a bureau — a new balance, a payment, a credit limit change, or a missed payment. Different accounts report on different schedules, so your score can shift at different times depending on which of your accounts just reported.

Is it bad to have no credit history at all?

It can make you harder to score, since scoring models need some track record to work from. This is sometimes called being "credit invisible." It's not a black mark, but it can limit your options until you establish some credit history.

Key Takeaways

A credit score is a calculated prediction of repayment risk, built from the information in your credit reports and generated by a scoring model like FICO or VantageScore — not a single fixed number you're assigned once.

Payment history and how much of your available credit you're using are typically the two biggest factors behind the number, and neither your income nor checking your own score has any effect on it. Reviewing your actual credit reports through AnnualCreditReport.com, now available weekly at no cost, is the most direct way to see what's actually feeding into your score and catch errors before they cause a problem.

Sources

This article is for general educational purposes only and does not constitute financial, investment, tax, or legal advice.

Last updated: August 2026