How Is My Credit Score Calculated in the UK?
Published 11th of October 2012·Updated 8 April 2026
Reviewed by: Reviewed for accuracy April 2026
Your credit score is calculated by the three UK credit reference agencies - Experian, Equifax, and TransUnion - using data from your credit file. Each agency uses its own formula, so you will have three different scores. All three are based on the same core factors: your payment history, how much of your available credit you use, the length of your credit history, and any negative marks such as defaults or county court judgements.
Short Summary
There is no single universal credit score in the UK. Experian, Equifax, and TransUnion each hold their own version of your credit file and calculate scores independently using their own models.
Payment history is the most influential factor. A record of paying on time, every month, across all your credit agreements is the strongest signal you can send to lenders.
Credit utilisation - the percentage of your available credit limit you are currently using - is the second most significant factor. Keeping it below 25 per cent is recommended by Experian and Equifax.
Negative marks such as defaults, county court judgements, and bankruptcies are weighted heavily. They remain on your file for six years, though their impact reduces as they age.
The exact algorithms are not published, but all three agencies are transparent about the factors they use. Understanding those factors is enough to manage and improve your score effectively.
What factors go into calculating my credit score?
The five main factors used by Experian, Equifax, and TransUnion are:
| Factor | Approximate weighting | What it measures |
|---|---|---|
| Payment history | Highest | Whether you pay on time across all accounts |
| Credit utilisation | High | How much of your credit limit you are using |
| Length of credit history | Moderate | How long your oldest account has been open |
| Credit mix | Lower | Whether you have a range of credit types |
| Recent applications | Lower | How many hard searches appear in the last 12 months |
These weightings are approximate; each agency uses its own proprietary model. The broad principle, however, is consistent across all three.
How does payment history affect my credit score?
Payment history is the single most important factor in your credit score. Lenders want evidence that you repay what you borrow, on time, consistently. Every credit agreement you hold - credit cards, loans, mortgages, mobile phone contracts, and even some utility accounts - reports your payment behaviour to the credit reference agencies each month.
One late payment can reduce your score noticeably. A pattern of late or missed payments will cause significant damage. Conversely, a long track record of on-time payments is the most reliable way to build a strong score over time.
What is credit utilisation and why does it matter?
Credit utilisation is the percentage of your total available credit limit that you are currently using. If you have a credit card with a £2,000 limit and an outstanding balance of £1,000, your utilisation on that card is 50 per cent. Experian recommends keeping utilisation below 25 per cent to avoid a negative impact on your score.
High utilisation suggests to lenders that you may be financially stretched. Reducing balances or requesting a credit limit increase (without spending more) can lower your utilisation ratio and improve your score relatively quickly.
Does the length of my credit history matter?
Yes. A longer credit history gives lenders more data to assess you. Closing old accounts - even ones you rarely use - can shorten your average account age and have a small negative effect on your score. If an old credit card has no annual fee and no outstanding balance, keeping it open and using it occasionally is generally better for your score than closing it.
The length of your oldest account and the average age of all your accounts both contribute to this part of the calculation.
How do negative marks affect my credit score calculation?
Negative marks are weighted heavily and remain on your credit file for six years from the date they are recorded. The main negative marks are:
- Missed or late payments (30 or more days late)
- Defaults (recorded when a lender closes an account due to non-payment)
- County court judgements (CCJs)
- Individual voluntary arrangements (IVAs)
- Bankruptcy
The impact of each mark reduces over time. A default from five years ago carries far less weight than one from six months ago. Consistent positive behaviour after a negative mark is the most effective way to rebuild your score while waiting for the mark to drop off.
Do all three credit agencies calculate the same score?
No. Experian, Equifax, and TransUnion each use their own scoring scale and their own formula. Your Experian score is out of 999; Equifax scores out of 1,000; TransUnion scores out of 710. The numbers are not directly comparable.
Not all lenders report to all three agencies, so your credit file may contain slightly different information at each one. Checking all three is worthwhile - errors at one agency will not be visible when you check a different one. You can check Experian via their website, Equifax via ClearScore (free), and TransUnion via Credit Karma (free).
What does not affect my credit score?
Several things are commonly misunderstood to affect credit scores but do not:
- Your salary or income (income is not reported to credit reference agencies)
- Your savings
- Checking your own credit score (a soft search; has no impact)
- Your age (though account age matters)
- Your employment status (lenders may ask, but it is not on your credit file)
- Whether you have been refused credit previously (the refusal itself is not recorded, only the hard search)
Frequently Asked Questions
Is my credit score the same at all three agencies?
No. Experian, Equifax, and TransUnion calculate separate scores using their own models and scales. The underlying data is similar but not always identical, because not all lenders report to all three agencies. Checking all three gives you the fullest picture.
How often is my credit score updated?
Credit scores are typically updated once a month, when lenders send updated account information to the credit reference agencies. The exact timing depends on when each lender reports and can vary by a few days.
Can I dispute information on my credit file?
Yes. If you believe information on your credit file is inaccurate, you can raise a dispute directly with the relevant credit reference agency. They are required to investigate and correct genuine errors. You can also add a Notice of Correction of up to 200 words to explain any unusual circumstances to future lenders.
Does being on the electoral roll improve my credit score?
Yes, indirectly. Being on the electoral roll confirms your address to lenders and helps verify your identity. It does not directly add points to your score, but it can improve your chances of being accepted for credit, which then allows you to build positive history. Registering takes a few minutes at gov.uk.
Do utility bills affect my credit score?
It depends on the provider. Some energy and water suppliers report payment history to the credit reference agencies; others do not. Services such as Experian Boost allow you to voluntarily add council tax and utility payments to your Experian file to help build your score if you have limited credit history.