Your credit score isn't a single universal number. Each of the UK's three main credit reference agencies — Experian, Equifax and TransUnion — calculates its own score from its own data. Lenders then apply their own internal scoring, affordability tests and product rules on top. We have our own view of what to aim for too.

In fact, lenders don't see your score at all. It's really a personal reference tool, there to help you understand your credit health and what's affecting it.

That said, some factors drag on every credit score, and those are worth knowing.

How your score is calculated#

Scoring models are set by the credit reference agencies, and they vary between them. Broadly, they're analysing:

  • Your history of paying bills
  • Credit and payment history
  • Total debt
  • Length of credit history
  • Balances and utilisation
  • Missed payments
  • Defaults
  • New credit applications
  • Public records
  • Whether you're on the Electoral Roll

All of that goes into the calculation — and because the models differ, your score differs between agencies.

The ranges aren't comparable one for one, so focus on your credit health rather than the number itself. Use the score as a guide to whether things need work, and to what's dragging on it.

What has the biggest impact#

There's no single biggest factor, but the heaviest negatives are missed payments, defaults, bankruptcies, IVAs and court judgments. All of them can stay on your file for six years, though their impact reduces over time.

Credit utilisation and debt levels come next. Sitting close to your card or overdraft limits can lower your score, because lenders read it as over-reliance on debt and a risk you'd struggle to repay them.

The length and depth of your credit history matters too. Little or no borrowing history can keep a score low simply because there's not much evidence you handle credit well.

On the positive side, the things that lift a score most are:

  • A current Electoral Roll listing, which is what lets a lender confirm you live where you say you do
  • An unbroken record of paying on time
  • Balances kept well below your limits
  • Accounts that have been open a long time and handled without incident
  • Restraint with new applications
  • Rent, utility and mobile contracts being reported

There's no single number that counts as a good score, but these are what push you towards lender confidence.

What doesn't affect your score at all#

Plenty of things you might worry about make no difference:

  • Checking your own report or score. It has no effect whatsoever. Credit eligibility checks — soft searches — don't affect it either.
  • Previous occupants at your address. Their finances are nothing to do with yours.
  • Your salary or criminal record. Neither appears on a credit report. Lenders will look at income separately for affordability checks.
  • A financial association on its own. Your report shows an associate's name only, never their credit data — so the link itself has no direct effect on your score.

Your credit score is purely a reflection of what's on your credit report.

But that last one comes with a catch worth understanding. A financial association doesn't touch your score, and it can still cost you an application.

When a lender receives an application from you, they may search your associate's details alongside your own and assess the two of you together. If that person carries defaults or a CCJ, it can count against your approval chances or the rate you're offered — because the lender is weighing whether their debts might become your problem.

So the sensible habit is to keep associations current. Anything left over from a relationship or joint account that's long finished is worth removing.

One more point on the Electoral Roll, which is listed above as a positive factor but does something more fundamental than that suggests. It's the index the rest of your report is matched against. If a lender can't find an Electoral Roll listing for you, they may struggle to locate your credit accounts at all — and some will decline on that basis alone, regardless of how good the history they can't see happens to be.

Common mistakes that pull a score down#

Small misunderstandings cost people more than they realise — and research suggests they're widespread. The most common:

  • Missing commitments such as mobile, Buy Now Pay Later, utility or minimum card payments.
  • Several full credit applications in a short period. These are recorded on your file, and lenders can't see the outcome of an application — so a cluster looks like reliance on credit and possible difficulty taking on more.
  • Running cards or overdrafts close to their limits, which again reads as difficulty repaying.
  • Forgetting to update your address on the Electoral Roll after moving.
  • Only checking one or two agencies, and missing errors or signs of fraud recorded at the third.

How to keep a healthy score#

Credit health is a journey, and small consistent steps compound. You can keep things in good order by:

  • Paying every account on time. Direct Debits take the risk of forgetting out of it. If you're struggling, speak to the lender before you miss a payment.
  • Monitoring your credit utilisation and only applying for credit when it genuinely suits your situation.
  • Using eligibility tools first and avoiding unnecessary applications, especially in the run-up to a mortgage.
  • Monitoring your credit report across all three agencies.
  • Getting your rent reported, if you rent.

If your score has dipped, don't panic — there are practical steps that will get it moving again.

Frequently asked questions#

How can I improve my credit score?

Improving a score takes time. The things that help most are registering on the Electoral Roll, paying bills and credit commitments on time, monitoring your credit utilisation, and correcting any errors on your report. Checking your report at all three agencies shows you where you stand, so you can build positive habits from there.

Why do the agencies give different scores?

Experian, Equifax and TransUnion each work out a score from the information they hold, on their own range and with their own method, so your score varies between them.

The key things to remember#

  • Lenders don't see your score; it's a reference tool for you.
  • Missed payments, defaults, bankruptcies, IVAs and CCJs are the heaviest negatives, and last six years.
  • High utilisation and a thin credit history both hold a score back.
  • Checking your own report, previous occupants, your salary and your criminal record have no effect.
  • Address changes not reflected on the Electoral Roll are a common, avoidable problem.
  • Checking only one agency means missing errors recorded at the others.