How Is My Credit Score Calculated in the UK?

Your credit score is one of the most important numbers in your financial life, and most people have no idea how it's actually worked out. It's not random. It's not based on your salary. And it's definitely not one single number that follows you everywhere.

In the UK, your credit score is calculated by three separate agencies: Experian, Equifax and TransUnion. Each one uses its own scoring model, which is why you'll see a different number depending on where you look. But they all draw on the same underlying data: your credit report.

This article explains exactly what goes into that calculation, which factors matter most, and what you can actually do to improve each one.

Your credit score is not your credit report

Before we dig into the calculation, this distinction matters. Your credit report is the raw data: every credit account you've had, your payment history, any missed payments, your address history and more. Your credit score is a number that summarises that data into something a lender can glance at quickly.

Think of it like a school report versus a final grade. The report has all the detail. The grade is the summary. But lenders often look at both, not just the score.

A good score opens doors. But the report is what's really behind the decision.

The six factors that determine your score

No agency publishes the exact formula (they're proprietary), but the industry is transparent about the categories that feed into the calculation. Here they are, roughly ranked by how much weight they carry.

1. Payment history - most important

This is the single biggest factor. Lenders want to know: do you pay on time? Every missed or late payment leaves a mark on your credit file for six years. Even one missed payment on a credit card, loan or phone contract can pull your score down significantly.

The good news is that consistent, on-time payments build your score steadily over time. If you do nothing else, just pay at least the minimum on everything, every month, on time.

Pro tip: Set up direct debits for at least the minimum payment on every credit account. It removes the risk of forgetting entirely.

2. Credit utilisation - very important

This measures how much of your available credit you're actually using. If you have a credit card with a £3,000 limit and you're carrying a £2,700 balance, your utilisation is 90%. That's a red flag for lenders.

The general rule is to keep utilisation below 30%, and ideally below 25%. So on a £3,000 limit, try to keep your balance under £900 at any given time.

Pro tip: Your balance is typically recorded on your monthly statement date, not the date you pay it off. If you want to show low utilisation, pay down the balance before the statement closes.

It's not about how much credit you have. It's about how little of it you use.

3. Length of credit history - important

Lenders like to see a long, stable track record. The older your credit accounts, the more data they have to judge you by. This is one reason closing an old credit card can sometimes lower your score, even if you never use it.

If you have a credit card you've held for years and it has no annual fee, keeping it open (even if you barely use it) can help your score by lengthening your average account age.

4. Types of credit - moderate

Having a mix of credit types, such as a credit card, a mobile phone contract and a personal loan, shows lenders you can handle different kinds of borrowing. This doesn't mean you should take out a loan just to diversify your file, but if you naturally have a mix, it works in your favour.

5. Hard searches - moderate

Every time you apply for credit, the lender runs a hard search on your file. Too many hard searches in a short period can make you look desperate for credit, which worries lenders. Each hard search stays on your file for 12 months and is visible to other lenders for that time.

Checking your own score (a soft search) does not affect it. Neither do eligibility checkers, which most comparison sites now offer. Use those before applying to avoid unnecessary hard searches.

6. Public records and electoral roll - foundational

Being registered on the electoral roll at your current address is one of the simplest things you can do to boost your score. It helps lenders verify your identity and address. If you're not registered, do it now at gov.uk. It takes two minutes.

Public records like CCJs (County Court Judgments), bankruptcies and IVAs have a severe negative impact and stay on your file for six years.

What the three UK agencies measure (and why scores differ)

Experian scores you out of 999. Equifax uses a scale of 0 to 700. TransUnion goes up to 710. They all pull from the same underlying data, but each weights the factors slightly differently and uses its own algorithm.

This means you might have a "good" score with one agency and an "excellent" score with another, even though nothing has changed. It's completely normal.

What matters is the trend across all three. If your score is improving on all of them, you're on the right track. If one is significantly lower, check that report specifically for errors or unusual entries.

Don't obsess over the exact number. Focus on the direction it's moving.

Things that hurt your score (that people don't expect)

  • Cancelling old credit cards. This shortens your average credit history and can spike your overall utilisation ratio if you carry balances on other cards.

  • Applying for multiple products in a short window. Each application adds a hard search. Space applications out by at least three months when possible.

  • Missing a payment by even one day. Some lenders report a payment as "missed" if it arrives after the due date, even by a single day. Direct debits solve this.

  • Having no credit at all. If you've never borrowed, lenders have nothing to assess you on. A thin file is almost as challenging as a bad one.

  • A financial link to someone with poor credit. Joint accounts and joint mortgages create a "financial association" on your file. If the other person has poor credit habits, it can affect your applications too.

Things that don't affect your score (even though people think they do)

  • Your salary. Your income is not on your credit report. Lenders may ask for it separately during an application, but it doesn't feed into your score.

  • Your savings. How much you have in the bank doesn't appear on your credit file.

  • Checking your own score. This is a soft search. Check it as often as you like.

  • Being declined for credit. The decline itself doesn't show up. But the hard search from the application does.

  • Your rent (usually). Most landlords don't report rent payments to credit agencies, though some services like CreditLadder and Canopy now let you opt in.

Your credit score reflects how you borrow and repay, not how much you earn or save.

How to check your score for free

You can check all three UK credit scores without paying a penny:

  • Experian: Free via the Experian app or MoneySavingExpert's Credit Club.

  • Equifax: Free via ClearScore.

  • TransUnion: Free via Credit Karma.

You're also legally entitled to request your full statutory credit report from each agency. Check all three, because lenders use different ones and an error on one might not appear on the others.

How to improve your credit score starting today

If your score isn't where you want it, here are the highest-impact actions, roughly in order of effect:

  • Register on the electoral roll at your current address via gov.uk. This is the quickest single win.

  • Set up direct debits for at least the minimum payment on every credit account.

  • Reduce your credit utilisation below 30% across all cards.

  • Check your report for errors. Incorrect addresses, accounts you don't recognise, or outdated financial associations can all be disputed and removed.

  • Stop applying for credit you don't need. Each application leaves a hard search. Use eligibility checkers first.

  • Keep old accounts open unless there's a good reason to close them.

Most improvements take one to three months to show up in your score. Be patient and consistent.

Where Mona fits

Mona helps you stay on top of the spending habits that feed into your credit health. She tracks your utilisation, nudges you before payment due dates, and flags when your spending patterns might be creeping in a direction that could affect your borrowing power. She connects via Open Banking so the picture is always up to date.

This article is for education only and is not financial advice. For free, impartial guidance on credit scores, MoneyHelper.org.uk (run by the UK government's Money and Pensions Service) and the FCA's ScamSmart tool are the best starting points.

The bottom line

Your UK credit score is built from six main factors: payment history, credit utilisation, length of history, credit mix, hard searches and public records. Payment history and utilisation carry the most weight. You have three separate scores from Experian, Equifax and TransUnion, and they'll each be slightly different.

The formula isn't a mystery. It rewards boring consistency: pay on time, don't max out your credit, keep old accounts alive, and don't apply for things you don't need.

A good credit score isn't about being rich. It's about being reliable.

Check all three of your scores for free today using Experian, ClearScore and Credit Karma. If you're not on the electoral roll, register at gov.uk right now. Those two steps alone can shift your score within weeks.

Join Mona’s early access waitlist

Join the waitlist

All articles

How Is My Credit Score Calculated in the UK?

Your credit score is one of the most important numbers in your financial life, and most people have no idea how it's actually worked out. It's not random. It's not based on your salary. And it's definitely not one single number that follows you everywhere.

In the UK, your credit score is calculated by three separate agencies: Experian, Equifax and TransUnion. Each one uses its own scoring model, which is why you'll see a different number depending on where you look. But they all draw on the same underlying data: your credit report.

This article explains exactly what goes into that calculation, which factors matter most, and what you can actually do to improve each one.

Your credit score is not your credit report

Before we dig into the calculation, this distinction matters. Your credit report is the raw data: every credit account you've had, your payment history, any missed payments, your address history and more. Your credit score is a number that summarises that data into something a lender can glance at quickly.

Think of it like a school report versus a final grade. The report has all the detail. The grade is the summary. But lenders often look at both, not just the score.

A good score opens doors. But the report is what's really behind the decision.

The six factors that determine your score

No agency publishes the exact formula (they're proprietary), but the industry is transparent about the categories that feed into the calculation. Here they are, roughly ranked by how much weight they carry.

1. Payment history - most important

This is the single biggest factor. Lenders want to know: do you pay on time? Every missed or late payment leaves a mark on your credit file for six years. Even one missed payment on a credit card, loan or phone contract can pull your score down significantly.

The good news is that consistent, on-time payments build your score steadily over time. If you do nothing else, just pay at least the minimum on everything, every month, on time.

Pro tip: Set up direct debits for at least the minimum payment on every credit account. It removes the risk of forgetting entirely.

2. Credit utilisation - very important

This measures how much of your available credit you're actually using. If you have a credit card with a £3,000 limit and you're carrying a £2,700 balance, your utilisation is 90%. That's a red flag for lenders.

The general rule is to keep utilisation below 30%, and ideally below 25%. So on a £3,000 limit, try to keep your balance under £900 at any given time.

Pro tip: Your balance is typically recorded on your monthly statement date, not the date you pay it off. If you want to show low utilisation, pay down the balance before the statement closes.

It's not about how much credit you have. It's about how little of it you use.

3. Length of credit history - important

Lenders like to see a long, stable track record. The older your credit accounts, the more data they have to judge you by. This is one reason closing an old credit card can sometimes lower your score, even if you never use it.

If you have a credit card you've held for years and it has no annual fee, keeping it open (even if you barely use it) can help your score by lengthening your average account age.

4. Types of credit - moderate

Having a mix of credit types, such as a credit card, a mobile phone contract and a personal loan, shows lenders you can handle different kinds of borrowing. This doesn't mean you should take out a loan just to diversify your file, but if you naturally have a mix, it works in your favour.

5. Hard searches - moderate

Every time you apply for credit, the lender runs a hard search on your file. Too many hard searches in a short period can make you look desperate for credit, which worries lenders. Each hard search stays on your file for 12 months and is visible to other lenders for that time.

Checking your own score (a soft search) does not affect it. Neither do eligibility checkers, which most comparison sites now offer. Use those before applying to avoid unnecessary hard searches.

6. Public records and electoral roll - foundational

Being registered on the electoral roll at your current address is one of the simplest things you can do to boost your score. It helps lenders verify your identity and address. If you're not registered, do it now at gov.uk. It takes two minutes.

Public records like CCJs (County Court Judgments), bankruptcies and IVAs have a severe negative impact and stay on your file for six years.

What the three UK agencies measure (and why scores differ)

Experian scores you out of 999. Equifax uses a scale of 0 to 700. TransUnion goes up to 710. They all pull from the same underlying data, but each weights the factors slightly differently and uses its own algorithm.

This means you might have a "good" score with one agency and an "excellent" score with another, even though nothing has changed. It's completely normal.

What matters is the trend across all three. If your score is improving on all of them, you're on the right track. If one is significantly lower, check that report specifically for errors or unusual entries.

Don't obsess over the exact number. Focus on the direction it's moving.

Things that hurt your score (that people don't expect)

  • Cancelling old credit cards. This shortens your average credit history and can spike your overall utilisation ratio if you carry balances on other cards.

  • Applying for multiple products in a short window. Each application adds a hard search. Space applications out by at least three months when possible.

  • Missing a payment by even one day. Some lenders report a payment as "missed" if it arrives after the due date, even by a single day. Direct debits solve this.

  • Having no credit at all. If you've never borrowed, lenders have nothing to assess you on. A thin file is almost as challenging as a bad one.

  • A financial link to someone with poor credit. Joint accounts and joint mortgages create a "financial association" on your file. If the other person has poor credit habits, it can affect your applications too.

Things that don't affect your score (even though people think they do)

  • Your salary. Your income is not on your credit report. Lenders may ask for it separately during an application, but it doesn't feed into your score.

  • Your savings. How much you have in the bank doesn't appear on your credit file.

  • Checking your own score. This is a soft search. Check it as often as you like.

  • Being declined for credit. The decline itself doesn't show up. But the hard search from the application does.

  • Your rent (usually). Most landlords don't report rent payments to credit agencies, though some services like CreditLadder and Canopy now let you opt in.

Your credit score reflects how you borrow and repay, not how much you earn or save.

How to check your score for free

You can check all three UK credit scores without paying a penny:

  • Experian: Free via the Experian app or MoneySavingExpert's Credit Club.

  • Equifax: Free via ClearScore.

  • TransUnion: Free via Credit Karma.

You're also legally entitled to request your full statutory credit report from each agency. Check all three, because lenders use different ones and an error on one might not appear on the others.

How to improve your credit score starting today

If your score isn't where you want it, here are the highest-impact actions, roughly in order of effect:

  • Register on the electoral roll at your current address via gov.uk. This is the quickest single win.

  • Set up direct debits for at least the minimum payment on every credit account.

  • Reduce your credit utilisation below 30% across all cards.

  • Check your report for errors. Incorrect addresses, accounts you don't recognise, or outdated financial associations can all be disputed and removed.

  • Stop applying for credit you don't need. Each application leaves a hard search. Use eligibility checkers first.

  • Keep old accounts open unless there's a good reason to close them.

Most improvements take one to three months to show up in your score. Be patient and consistent.

Where Mona fits

Mona helps you stay on top of the spending habits that feed into your credit health. She tracks your utilisation, nudges you before payment due dates, and flags when your spending patterns might be creeping in a direction that could affect your borrowing power. She connects via Open Banking so the picture is always up to date.

This article is for education only and is not financial advice. For free, impartial guidance on credit scores, MoneyHelper.org.uk (run by the UK government's Money and Pensions Service) and the FCA's ScamSmart tool are the best starting points.

The bottom line

Your UK credit score is built from six main factors: payment history, credit utilisation, length of history, credit mix, hard searches and public records. Payment history and utilisation carry the most weight. You have three separate scores from Experian, Equifax and TransUnion, and they'll each be slightly different.

The formula isn't a mystery. It rewards boring consistency: pay on time, don't max out your credit, keep old accounts alive, and don't apply for things you don't need.

A good credit score isn't about being rich. It's about being reliable.

Check all three of your scores for free today using Experian, ClearScore and Credit Karma. If you're not on the electoral roll, register at gov.uk right now. Those two steps alone can shift your score within weeks.

Join Mona’s early access waitlist

Join the waitlist

All articles