How do credit scores work? A credit score is a number, calculated from the records in your credit report, that estimates how likely you are to fall seriously behind on repayments. Lenders use it to decide whether to lend, and often at what rate. It is not a measure of wealth or of character. It is a statistical prediction built from a narrow set of facts about how you have handled credit before.
This article explains what goes into a score, how the factors are weighted, what moves it up and down, how long records last, and how the system differs between countries. It is general information about how the mechanism works.
How do credit scores work?
Three things are involved, and they are often confused.
The credit report is the record: your credit accounts, balances, payment history and any defaults, collected by credit reference agencies from lenders. In the United States there are three main agencies, Equifax, Experian and TransUnion.
The scoring model is the formula that turns the report into a number. It is built by analysing millions of past borrowers to find which patterns in their reports predicted later missed payments.
The score is the result for you, at a particular moment, from a particular model applied to a particular report.
That last point explains why people often have several different scores. Different agencies may hold slightly different records, and lenders use different models and versions. A change in any of the three changes the number.
A credit score does not measure how much money you have. It measures how you have handled money you borrowed.
Where credit scores came from
Lenders have always judged creditworthiness, but for most of history they did it by reputation, references and a loan officer's impression, which was slow and often unfair. Statistical scoring replaced much of that judgement with a consistent formula.
The company Fair, Isaac and Company, founded in 1956, built early scoring systems for individual lenders. In 1989 it introduced the first general-purpose FICO score, designed to work across lenders using data from the credit agencies. FICO scores are now used in the large majority of US lending decisions. In 2006 the three agencies launched a competing model, VantageScore.
Both use a range of 300 to 850, with higher scores indicating lower predicted risk.
The five factors in a FICO score
FICO publishes the approximate weight each category carries for the general population. The exact calculation is proprietary, and the weights vary somewhat by individual profile, but the categories and rough proportions are public.
| Factor | Weight | What it looks at |
|---|---|---|
| Payment history | 35% | Whether past payments were made on time, and how late any missed ones were |
| Amounts owed | 30% | How much you owe, especially relative to your available credit limits |
| Length of credit history | 15% | How long accounts have been open, on average and for the oldest |
| New credit | 10% | Recently opened accounts and recent applications |
| Credit mix | 10% | The variety of credit types, such as cards, instalment loans and mortgages |
The first two together make up about two thirds of the score. That is the practical heart of it: paying on time, and not using too large a share of the credit available to you.
Payment history: the largest single factor
The model's central question is whether you will pay, and the best predictor of that turns out to be whether you have paid before. A single payment that is 30 or more days late can lower a score noticeably, and later ones more so. Defaults, accounts sent to collection and bankruptcies weigh most heavily of all.
Recency matters. A late payment from last month counts for far more than one from five years ago, and the effect fades as it ages, especially if everything since has been paid on time.
How this is taught inside Astra Trainer
The Money Systems direction in the Business & Finance world runs to twenty courses covering money creation, credit and central bank operations, starting from courses such as Money, Currency, and Credit.
Credit scoring is where that system meets an individual. Banks create most money by lending, and scoring is one of the main ways they decide who to lend to and at what price. Lessons take about five minutes and a guide walks you through anything strange.
Amounts owed and credit utilisation
The second factor is less intuitive. It is not only how much you owe, but how much of your available revolving credit you are using, known as credit utilisation.
If you have credit card limits totalling $10,000 and balances of $8,000, your utilisation is 80 percent, which models read as a sign of strain, even if every payment is on time. The same balances against $40,000 of limits would be 20 percent, and read quite differently. Lower utilisation is generally associated with better scores; commonly quoted guidance suggests keeping it well below 30 percent, and people with the highest scores tend to use far less.
Utilisation is calculated from the balances reported, usually at the statement date, so it can change quickly in either direction, unlike payment history, which builds slowly.
Check yourselfYou have an old credit card you no longer use. Would closing it raise your score, lower it, or leave it unchanged? Commit to an answer, and a reason, before reading on.Show the answerHide the answer
It can lower it, for two reasons. Closing the card can shorten the average age of your accounts, and older accounts give the model more evidence. It also removes that card's limit from your total available credit, so the same balances now use a larger share of it, and utilisation rises.
Length of history, new credit and mix
Length of history rewards time. Older accounts give the model more evidence. This is why closing an old, unused card can sometimes lower a score: it can shorten the average age of accounts and reduce total available credit, raising utilisation.
New credit reflects recent applications. Each application for credit usually creates a hard inquiry, which can lower a score slightly for a short period. Checking your own score or report is a soft inquiry and does not affect it. Several applications close together can suggest someone is under financial pressure, although scoring models generally treat multiple inquiries for the same kind of loan, such as rate shopping for a mortgage, within a short window as one.
Credit mix looks at whether you have handled different types of credit. It is the smallest factor, and not a reason in itself to take on debt.
How long records last
In the United States, under the Fair Credit Reporting Act, most negative information, such as late payments and accounts in collection, can stay on a credit report for seven years. Some bankruptcies can remain for ten. The effect on the score usually fades well before the record disappears, as newer, positive history accumulates.
In the UK, information generally stays on a credit file for six years. Rules differ in other countries, and some rely less on a single numeric score.
General information, not financial advice. This article explains how credit scoring works in general terms. Scoring models, reporting rules and lender criteria differ by country, agency and product, and change over time. For decisions about borrowing or repairing credit, check the official sources in your country and consider speaking to a qualified, regulated adviser. Be wary of services that promise to remove accurate negative information for a fee.
Checking your report, and why it matters
Because the score is only as good as the report behind it, errors in the report produce errors in the score. Accounts that are not yours, payments wrongly marked late and debts listed twice are all found often enough to matter.
In the US, you can get free copies of your credit reports from each of the three main agencies through AnnualCreditReport.com, the official site set up under federal law, and dispute inaccuracies directly with the agency. In the UK, the main agencies offer free access to your report. Checking your own report does not affect your score.
For the bigger picture of how credit fits into the money system, the article on how banks create money explains why lending decisions matter so much, and how compound interest works shows what the interest rate attached to a score actually costs over time.
Why money habits are built slowly
A credit score rewards exactly the kind of behaviour that is hard to sustain: small, regular, on-time actions over years. Understanding the mechanism is the easy part. Keeping the habit is the work.
Astra Trainer is built around habits. Quizzes follow each topic and each course ends with a ten-question final exam, while daily quests, points and a streak keep five-minute lessons going, with a streak shield for the day that goes wrong. A Circle gives you a small group with a shared weekly goal and live sessions, useful for money topics people rarely discuss openly.
Try it now, on your own credit file
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The second and third lines cover amounts owed and payment history, about two thirds of a FICO score between them, so a gap there matters more than one in the last line. The first is how errors in the report get caught.
What to take from this
A credit score is a statistical prediction of the chance you will fall seriously behind on payments, calculated from your credit report by a scoring model.
FICO, introduced in 1989, weights payment history at 35 percent and amounts owed at 30 percent, so paying on time and keeping utilisation low account for about two thirds of the score.
Negative records fade in effect over time and, in the US, most drop off a report after seven years. Errors in the report are common enough that checking it is worthwhile.
Which is why the most useful answer to how do credit scores work is that they reward consistency more than anything else, and measure how you borrow, not how much you have.
Test yourself
Question 1 of 3
A borrower checks two apps on the same day and sees two different scores. What does the article say is the likely reason?
How do credit scores work?
A scoring model analyses the records in your credit report, such as payment history, balances and account age, and turns them into a number predicting how likely you are to fall seriously behind on payments. Lenders use it to decide whether to lend and at what rate.
What are the five factors of a FICO score?
Payment history, about 35 percent; amounts owed, about 30 percent; length of credit history, 15 percent; new credit, 10 percent; and credit mix, 10 percent. The exact weights vary by individual profile.
Does checking my own credit score lower it?
No. Checking your own score or report is a soft inquiry and does not affect it. Applying for new credit usually creates a hard inquiry, which can lower a score slightly for a short time.
How long do late payments stay on a credit report?
In the United States, most negative information, including late payments, can stay on a credit report for up to seven years, and some bankruptcies for ten. In the UK, records generally stay for six years. The effect on the score fades before the record disappears.
Where can I learn how credit and money work in short lessons?
The Money Systems direction inside the Business & Finance world of Astra Trainer runs to twenty courses covering money creation, credit and central bank operations, in five-minute lessons with quizzes. The first lesson needs no card.
Where this leads. How to Get Better With Money: The Order to Learn It shows where credit fits among the money skills worth building, and in what order.
