Why Your Credit Score Is Different on Every Agency

You check your Experian score: 780. Not bad. You check ClearScore (Equifax): 420. Panic. You check Credit Karma (TransUnion): 560. Confusion.

Three agencies, three completely different numbers, and you have no idea which one actually matters for your mortgage. The answer is surprisingly simple: none of them, at least not in the way you think.

Here's why the scores differ, what mortgage lenders actually look at, and how to use all three agencies to your advantage.

The Three UK Credit Reference Agencies

The UK has three main credit reference agencies (CRAs) that collect and maintain credit data on consumers:

Experian

The largest CRA in the UK. Their consumer score runs from 0 to 999. You can access your Experian score directly through their website or app (free basic service or paid premium).

Equifax

The second major CRA. Their consumer score runs from 0 to 1000 (though this changed from 0-700 in previous years). You can access your Equifax data free through ClearScore.

TransUnion

The third CRA (formerly Callcredit). Their consumer score runs from 0 to 710. You can access your TransUnion data free through Credit Karma.

Right away, you can see why comparing the numbers is meaningless. An Experian score of 700 and a TransUnion score of 700 represent completely different things on completely different scales. It's like comparing temperatures in Celsius and Fahrenheit — the numbers aren't equivalent.

Why the Scores Differ

There are three main reasons your scores differ across agencies:

1. Different Scoring Models

Each agency has developed its own proprietary algorithm for calculating your consumer score. They weight factors differently:

• One might place more emphasis on your payment history
• Another might weight your credit utilisation more heavily
• A third might factor in the length of your credit history differently

Even with identical data, the three agencies would produce different scores because they're using different formulas.

2. Different Data

This is the more important reason. Not all lenders and creditors report to all three agencies. A credit card company might report to Experian and Equifax but not TransUnion. A mobile phone provider might only report to TransUnion.

This means each agency holds a slightly different picture of your credit history. Common discrepancies include:

• An account showing on one agency but not another — if a creditor only reports to two of the three agencies, the third won't know about that account
• Different balances — lenders report at different times during the month, so balances may not match exactly
• A default on one file but not another — if the creditor only reports to specific agencies
• Different search histories — some lenders search one agency, others search two or all three

3. Different Timing

Creditors don't all report on the same date. One might update monthly on the 1st, another on the 15th. Depending on when you check your file, the data might be at different stages of the monthly reporting cycle.

What Mortgage Lenders Actually Use

Here's the key insight that most people don't know: mortgage lenders don't use the consumer credit score you see on Experian, ClearScore, or Credit Karma.

Instead, they use one or more of the following:

Their Own Internal Scoring Model

Most large mortgage lenders have their own proprietary credit scoring system. They pull data from one or more credit reference agencies and feed it into their own algorithm, which is tuned to their specific lending criteria and risk appetite.

This means two lenders looking at exactly the same credit file can reach different conclusions. One might approve you; the other might decline. Their internal models weight different factors differently.

The Raw Data

Some lenders — particularly building societies and specialist lenders who manually underwrite — look directly at the underlying data on your credit file rather than relying on a score. They're reading the individual entries: payment history, defaults, CCJs, searches, existing commitments.

This is why a credit report interpreter is more useful than obsessing over your score — the data tells the story, not the number.

Which Agency Do Lenders Check?

Different lenders check different agencies. Some check only one, others check two, and a few check all three:

• Many high street banks primarily use Experian
• Some building societies use Equifax
• Several specialist lenders use a combination
• Some lenders use Call Validate or other services that pull from multiple agencies simultaneously

You generally don't know in advance which agency your mortgage lender will check. This is another reason to make sure all three files are accurate.

What Actually Matters: Data, Not Scores

If your credit score isn't what mortgage lenders use, what should you focus on? The underlying data:

Payment History

Every monthly payment (or missed payment) on every credit account. This is the bedrock of your credit file. Mortgage lenders look at this directly — not as a score component, but as actual evidence of how you handle financial commitments.

Defaults and CCJs

These are binary: you either have them or you don't. Their age, size, number, and satisfaction status are what matter — not how they affect your consumer score.

Outstanding Debt and Commitments

Your total debt and monthly commitments directly affect how much a lender will offer you. This is an affordability calculation, not a credit score calculation.

Hard Searches

Recent credit applications show on your file. Too many in a short period can concern lenders. But this is visible data, not a hidden scoring factor.

Electoral Roll

Whether you're registered. A simple yes/no that confirms your identity and address.

Length and Type of Credit History

How long you've had credit accounts and what types (credit cards, loans, mortgages). A longer, more diverse history is generally better.

Common Discrepancies and What They Mean

"My Experian Score Is High but ClearScore Is Low"

This usually means there's negative information on your Equifax file that doesn't appear on Experian. Check both files carefully for differences — look for accounts, defaults, or searches that appear on one but not the other.

"I Have a Default on TransUnion but Not Experian"

The creditor who registered the default may only report to TransUnion. The default is real, even if it's only on one file. If a mortgage lender checks TransUnion (or uses a multi-agency search), they'll see it.

"My Score Dropped for No Reason"

Common causes:

• A new hard search was recorded (you applied for something)
• Your credit card balance was reported at a high point in the month (utilisation spike)
• An old account closed, reducing your available credit
• An account you forgot about went into arrears

Check the data, not just the number. The score movement always has an explanation in the underlying data.

"All Three Scores Are Different but I've Done Nothing Different"

This is normal. Because they use different scales, different algorithms, and hold slightly different data, the numbers will almost never match. Don't try to reconcile them — instead, check that the underlying data on each is accurate.

How to Use All Three Agencies Effectively

Here's a practical approach to credit file management before a mortgage application:

Check All Three, Focus on the Data

1. Experian — check directly at experian.co.uk (free basic account)
2. Equifax — check via ClearScore (free)
3. TransUnion — check via Credit Karma (free)

On each, look at:

• All accounts listed (are they all yours?)
• Payment history on each account (any missed payments?)
• Defaults (any registered?)
• Searches (any you don't recognise?)
• Financial associations (any unexpected links?)
• Electoral roll (are you registered?)
• Addresses (are they correct?)

Fix Any Errors

If you find incorrect information on any file, dispute it directly with the credit reference agency. They have 28 days to investigate and respond. If the error is confirmed, it must be corrected or removed.

Common errors include:

• Accounts that aren't yours (possibly identity theft or mistaken identity)
• Incorrect payment statuses
• Wrong addresses
• Outdated financial associations
• Debts that have been paid but still show as outstanding

Add a Notice of Correction

If there's information on your file that's technically accurate but doesn't tell the full story (a default caused by a billing dispute, for example), you can add a notice of correction — up to 200 words explaining your side. Mortgage lenders are required to read this, and it can provide important context.

For a full guide on reading and understanding your credit reports, see our credit report interpreter.

The Bottom Line

Your credit score isn't a single number, and the number you see isn't what mortgage lenders use anyway. The consumer scores from Experian, ClearScore, and Credit Karma are useful as indicators — they help you track whether your credit health is improving or deteriorating. But they're not the decision-making tool.

What matters is the data underneath. Accurate records, clean payment history, resolved debts, and no surprises. Check all three agencies, fix any errors, understand what's there, and let a specialist broker worry about which lender's scoring model best fits your profile.

Stop comparing numbers. Start managing data.

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This is educational content, not financial advice. Your situation is unique — speak to a qualified mortgage broker before making any decisions.