How Credit Scores Work — and How to Improve Yours

Your credit score is one of the most consequential numbers in personal finance — it determines whether you get approved for a mortgage, what interest rate you pay on loans, and sometimes even whether a landlord will rent to you. Yet most people have only a vague idea of what it actually measures or how to improve it.

What is a credit score?

A credit score is a three-digit number — typically between 300 and 850 in the US (FICO scale) or 0–999 in the UK (Experian) — that summarises your history of borrowing and repayment. Lenders use it as a quick signal of how likely you are to repay a new loan.

In the UK, the three main credit reference agencies are Experian, Equifax, and TransUnion. Each uses slightly different scales and data, so your score will differ between agencies. In the US, most lenders use FICO scores, though VantageScore is also widely used.

What makes up your credit score?

FICO breaks down its score into five weighted components:

• Payment history (35%) — the most important factor. A single missed payment can drop your score by 60–110 points. Payments more than 30 days late are reported to credit agencies.
• Credit utilisation (30%) — how much of your available credit you're using. Staying below 30% is widely recommended; below 10% is better for top scores.
• Length of credit history (15%) — older accounts help. Closing a long-standing account can shorten your average account age and hurt your score.
• Credit mix (10%) — having different types of credit (credit cards, loans, mortgage) can help, though this is the least important factor.
• New credit enquiries (10%) — each hard credit search (for a loan, card, or mortgage application) temporarily reduces your score by 5–10 points.

How to check your credit score

UK: All three agencies offer free credit reports. Experian and Equifax offer free monthly score checks via their apps. ClearScore (uses Equifax data) and Credit Karma (TransUnion) are also free permanently.

US: You're entitled to one free credit report per year from each of the three major bureaus via AnnualCreditReport.com. Many banks and credit cards now offer free FICO score access as a standard feature.

Checking your own score is a soft enquiry and does not affect your score.

How to improve your credit score

These actions have the most impact, roughly in order of effectiveness:

• Never miss a payment — set up direct debits for at least the minimum on every account. One missed payment can take 12–24 months to stop materially affecting your score.
• Reduce your credit utilisation — if you have a £5,000 credit limit and use £3,500, your utilisation is 70%. Pay it down to below £1,500 and your score will often jump within one billing cycle.
• Register on the electoral roll (UK) — this is one of the fastest score improvements available in the UK. Lenders use it to verify your address and identity.
• Don't close old accounts — a long-standing account with no balance is a free credit score booster. Only close accounts with fees you can't justify.
• Avoid multiple applications in quick succession — if you're shopping for a mortgage, most lenders recommend doing all applications within a 14–45 day window, as credit bureaus treat clustered mortgage enquiries as a single hard pull.
• Fix errors on your report — approximately 1 in 5 credit reports contains a material error. Dispute any inaccuracies directly with the credit bureau.

How long does it take to improve?

Small improvements (reducing utilisation, registering on the electoral roll) can show within 30–60 days. Recovering from a missed payment or default typically takes 2–4 years for the impact to fade significantly, even if the account is brought up to date. A bankruptcy stays on a UK credit file for 6 years; in the US, Chapter 7 bankruptcy stays for 10 years.

The good news: the impact of negative marks fades over time, and consistent positive behaviour — always paying on time, keeping utilisation low — consistently outweighs older negatives.

Common credit score myths debunked

Myth: Checking your own score damages it. False. Checking your own credit report is a "soft enquiry" and has zero impact on your score. Only "hard enquiries" — from lenders when you apply for credit — cause a temporary dip.

Myth: Closing unused credit cards improves your score. Often the opposite. Closing an old card reduces your total available credit (pushing utilisation up) and can shorten your average account age. Keep old accounts open unless they carry an annual fee you can't justify.

Myth: You have one credit score. In the UK you have three (one from each major bureau) and they will differ. In the US, you have dozens of variants of FICO scores, weighted differently for different lending decisions — a mortgage lender uses different weighting than a credit card issuer.

Myth: A higher income means a better credit score. Income is not a factor in your credit score. A high earner who misses payments will have a worse score than a lower earner who pays everything on time. Use our loan calculator to see how your credit score affects the true cost of a loan.