How Credit Scores Work: The Main Factors, Explained Simply
Where credit scores come from, the general factors that tend to move them, and a few common misunderstandings.
A credit score is a three-digit number that lenders, card issuers and some other businesses use to estimate how likely you are to repay borrowed money on time. It can affect whether you're approved for credit and the terms you're offered. The exact formulas aren't public, but the main ideas behind credit scores are fairly simple. This guide covers where scores come from, the factors that generally matter, and some common misunderstandings.
Where a credit score comes from
Your score is calculated from the information in your credit reports. A credit report is a record of how you've handled credit accounts such as credit cards, auto loans, student loans and mortgages. In the United States, the three nationwide credit bureaus are Equifax, Experian and TransUnion. Lenders send account information to one or more of them, usually about once a month.
A scoring model then reads a credit report and turns it into a number. The two most widely known developers of scoring models are FICO and VantageScore, and each has released several versions over the years. Many common versions use a range of roughly 300 to 850, where higher numbers suggest lower risk to a lender, though some versions use different ranges.
Because there are several models and three bureaus, and because not every lender reports to every bureau, you don't have just one credit score. It's normal to see somewhat different numbers depending on where you look and when.
The main factors, in general terms
Scoring companies don't publish their complete formulas, and the importance of each factor can vary by model and from one person's credit file to another. Still, widely used models look at the same broad categories of information.
Payment history
Whether you pay on time is generally described as the single most influential factor. Late payments, accounts sent to collections and bankruptcies can weigh on a score. Lenders generally don't report a payment as late until it is at least 30 days past due. Most negative items can remain on your credit reports for up to seven years, although their effect usually fades as they age.
Credit utilization
For credit cards and other revolving accounts, scoring models look at how your balances compare with your credit limits. This is called your credit utilization ratio. Lower utilization is generally viewed more favorably. You may see a rule of thumb to keep it below 30 percent, but that is general guidance rather than a hard cutoff. Models may look at utilization across all your cards and on each card individually.
One detail surprises many people: the balance used is usually the one your card issuer reports, which is often the balance on your statement. That means utilization can look high even if you pay your bill in full every month.
Length of credit history
Models consider how long you've had credit, which can include the age of your oldest account, your newest account and the average age of your accounts. A longer history gives lenders more information to go on. This factor mostly improves with time, which is one reason people who are new to credit tend to have thinner files.
New credit
When you apply for credit, the lender usually makes a hard inquiry, which appears on your credit report. A hard inquiry typically has a small, temporary effect on a score, but several applications or new accounts in a short period can signal higher risk. Checking your own score, and many preapproval offers, involve soft inquiries, which don't affect your score. For certain loan types, such as mortgages and auto loans, many models treat several inquiries made within a short shopping window as a single inquiry.
Credit mix
Experience with different types of credit, such as revolving accounts like credit cards and installment loans like an auto loan, can play a smaller role. It generally isn't a reason on its own to take on a loan you don't need.
Example: how utilization is calculated
The table below is a hypothetical example using round, illustrative numbers. It shows how the same debt can produce different utilization ratios.
| Example scenario | Total balances | Total credit limits | Utilization |
|---|---|---|---|
| Example 1: Card A has $500 of a $2,000 limit; Card B has $1,000 of a $3,000 limit | $1,500 | $5,000 | 30% |
| Example 2: The same two cards after paying balances down to $500 in total | $500 | $5,000 | 10% |
| Example 3: Card A is paid off and closed; Card B carries a $1,500 balance | $1,500 | $3,000 | 50% |
In the third example, the total owed didn't grow, but closing a card removed part of the available credit, so the ratio rose. This is one reason closing a card can affect utilization even when you owe nothing on that card.
What isn't in your credit score
Credit scores are based on credit report information, so some things people expect to matter aren't part of the calculation. Your income isn't on your credit report, although lenders often ask about it separately when you apply. Credit reports don't include your race, religion or national origin, and widely used scoring models don't consider characteristics like these. And checking your own score doesn't lower it.
Habits that support a healthy score
Check your credit reports
You can get free copies of your reports from each of the three nationwide bureaus through AnnualCreditReport.com, the official source for free reports under federal law. Look for accounts you don't recognize, late payments you believe are wrong, or incorrect balances.
Dispute errors
If something is inaccurate, you can dispute it with the credit bureau that shows the error and with the company that supplied the information. Keep copies of everything you send.
Pay every bill on time
Setting up automatic payments for at least the minimum due can help keep a payment from slipping through the cracks.
Keep balances manageable
Using a smaller share of your available credit generally works in your favor. Paying down balances, or making a payment before your statement closes, can lower the balance that gets reported.
Apply for new credit when you need it
Spacing out applications limits hard inquiries and new accounts.
Give it time
Many positive factors, like a long record of on-time payments, build gradually. There's no reliable shortcut.
Does checking my own credit score lower it?
No. Checking your own score or report is a soft inquiry, which doesn't affect your credit score. Hard inquiries happen when a lender reviews your credit because you applied for credit.
Why do I see different scores in different places?
Scores can differ because they come from different scoring models or versions, are based on reports from different bureaus, or were calculated on different dates. Small differences are normal.
Do I need to carry a balance on a credit card to build credit?
No. Paying your statement balance in full each month still shows on-time payments, and it generally lets you avoid interest on purchases.
How long do late payments stay on my credit report?
Most negative items, including late payments, can stay on your credit reports for up to seven years. Their effect on your score usually lessens over time, especially as newer, positive activity is added.
What counts as a good credit score?
There isn't one universal cutoff. Each lender sets its own standards and may use a different scoring model. In general, a higher score within a model's range suggests lower risk and may qualify you for better terms.