Your credit score quietly decides whether you can borrow, how much you’ll pay for it, and sometimes whether you can rent an apartment — yet almost nobody is taught how it’s calculated. Here’s exactly what goes into it and what actually moves the number.
Key takeaways
- A credit score predicts how likely you are to repay borrowed money — it isn’t a measure of wealth.
- Payment history and how much of your available credit you use make up about 65% of a FICO score.
- Checking your own score never lowers it. Only applications for new credit can.
- You’re entitled to free copies of your credit reports — and errors on them are common.
What a credit score actually measures
A credit score is a three-digit number, most commonly on a 300–850 scale, that estimates the likelihood you’ll repay borrowed money on time. Lenders use it to decide whether to approve you and what interest rate to offer.
An important clarification: your score says nothing about your income, savings or net worth. Someone with a large salary and no borrowing history can have a lower score than someone earning far less who has used credit responsibly for a decade. It measures borrowing behaviour, not financial success.
The most widely used model is the FICO Score, with VantageScore as the main alternative. They weigh things slightly differently, which is why the number you see in a free app may not match what a lender pulls.
The five factors — and how much each counts
FICO publishes the approximate weighting of its scoring factors:
| Factor | Weight | What it looks at |
|---|---|---|
| Payment history | 35% | Whether you’ve paid on time; late payments, defaults, collections |
| Amounts owed | 30% | How much of your available credit you’re using |
| Length of credit history | 15% | Age of your oldest and average accounts |
| New credit | 10% | Recent applications and newly opened accounts |
| Credit mix | 10% | Variety of account types — cards, loans, mortgage |
The practical implication is clear: the first two factors are roughly two-thirds of your score. Paying on time and not maxing out your available credit matter far more than anything else, and chasing the smaller factors is largely wasted effort.
Payment history (35%)
The single biggest lever, and the most damaging when it goes wrong. A payment generally isn’t reported as late until it’s 30 days past due — so being a few days late is bad for fees but usually not for your score. Once reported, a late payment can stay on your report for around seven years, though its impact fades over time.
Amounts owed and credit utilisation (30%)
Credit utilisation is the percentage of your available credit you’re currently using. If you have $10,000 in total limits and a $3,000 balance, that’s 30% utilisation.
Lower is generally better. A widely repeated rule of thumb is to stay under 30%, though scores often improve further below that. Crucially, utilisation is recalculated whenever balances are reported — meaning it has no long memory. Pay a balance down and the improvement typically shows up within a cycle or two.
What doesn’t affect your score
- Your income or savings. Lenders consider these separately, but they aren’t in the score.
- Checking your own score or report. This is a soft inquiry and has no effect whatsoever.
- Using a debit card. Debit spending isn’t borrowing and isn’t reported.
- Carrying a balance to “build credit.” A persistent myth — paying in full still demonstrates on-time payment, and avoids interest.
Practical ways to improve it
- Automate at least the minimum paymentThis protects the 35% factor. Automating the minimum prevents a missed payment; you can always pay more manually.
- Bring utilisation downPay balances before the statement date, not just the due date — the reported figure is usually the statement balance. Requesting a limit increase also lowers utilisation without changing your spending.
- Leave old accounts openLength of history counts, and closing accounts shortens it while shrinking your available credit.
- Apply for new credit sparinglyEach application creates a hard inquiry. Several in a short window looks like financial stress — though rate-shopping for a single mortgage or car loan within a short period is typically treated as one inquiry.
- Check your reports and dispute errorsErrors are more common than people expect, and a mistaken late payment or account that isn’t yours can cost you real money in interest.
What counts as a “good” score?
Using the common FICO bands: below 580 is generally considered poor, 580–669 fair, 670–739 good, 740–799 very good, and 800+ exceptional. Most lending advantages are captured by the time you reach the mid-700s — pushing from 780 to 830 rarely changes the rates you’re offered in any meaningful way.
The terms, explained
- FICO Score
- The most widely used credit scoring model in the US, ranging from 300 to 850.
- Credit report
- The underlying record of your borrowing history held by the credit bureaus. Your score is calculated from it — they aren’t the same thing.
- Credit bureaus
- The three main US agencies that compile credit reports: Equifax, Experian and TransUnion. Their files can differ, so your score can too.
- Credit utilisation
- The share of your available credit currently in use, expressed as a percentage. A major score factor with no long-term memory.
- Hard inquiry
- A credit check triggered when you apply to borrow. It can slightly reduce your score and stays on your report for about two years.
- Soft inquiry
- A check that doesn’t affect your score — such as viewing your own score, or a pre-approval offer.
- Thin file
- Having too little credit history to generate a score. Common for young adults and newcomers to a country.
Credit scoring is one of those topics that’s easier to follow with the numbers on screen — our Money video explainers walk through it visually.
Frequently asked questions
Does checking my credit score lower it?
No. Checking your own score or report is a soft inquiry and has no impact. Only hard inquiries — from actual applications to borrow — can affect it, and usually only slightly.
How long does it take to improve a credit score?
It depends what’s holding it back. Utilisation improvements can show within one or two billing cycles. Negative marks like late payments fade gradually and generally drop off after about seven years.
Why do I have different scores in different places?
Because there are multiple scoring models (FICO and VantageScore, each with versions) and three bureaus holding slightly different data. Differences of a few dozen points between sources are normal.
How do I get my credit report for free?
In the US you’re entitled to free reports from all three bureaus via AnnualCreditReport.com, the only federally authorised source. Reviewing them is worth doing regularly — errors are common and disputing them is free.
Sources & further reading
- CFPB — Credit Reports and Scores
- AnnualCreditReport.com — official free reports
- USA.gov — Credit reports and scores
