Your Experian, Equifax or TransUnion "score" (often shown as a number out of 999 or 700) is a generic consumer score. Mortgage lenders don't see that number at all — they pull your raw credit file and run it through their own internal scorecard, which weighs things differently for every lender. A "good" consumer score doesn't guarantee a mortgage approval, and a mediocre one doesn't automatically rule you out.
Why your app's credit score isn't what the lender sees
Apps like the ones from Experian, ClearScore (Equifax data) and Credit Karma (TransUnion data) each generate their own proprietary score, on their own scale, using their own weighting. These are useful as a general health check and for spotting errors — but no mortgage lender bases a decision on that headline number.
What actually happens: you apply for a mortgage, and the lender requests your full credit file (or a summary of it) from one or more of the three credit reference agencies. They then run the underlying data — not the agency's score — through their own internal risk model, alongside your income, outgoings and the specifics of the property. Two lenders can look at the exact same credit file and reach different conclusions, because their internal scorecards are built differently and weighted for their own risk appetite.
This is why being declined by one lender doesn't mean you'll be declined by all of them. It's also why a broker who knows which lenders are typically more flexible on your specific situation (thin credit file, a missed payment two years ago, high existing debt) can matter more than chasing a higher "score" on an app.
What's actually in your file that lenders care about
- Payment history: Missed or late payments on credit cards, loans, utility bills or your phone contract — especially anything recent or repeated.
- Existing debt and credit utilisation: How much of your available credit you're using, and your total committed monthly outgoings versus income.
- Electoral roll registration: Being registered to vote at your current address is one of the simplest, most overlooked ways lenders verify your identity and address history.
- Credit history length and mix: A completely empty credit file ("thin file") can actually work against you, because lenders have nothing to assess — having some responsibly managed credit, even a phone contract paid on time, helps build a track record.
- Search footprint: A cluster of hard credit searches in a short window (multiple credit card or loan applications) can look like financial stress, even if each individual application was harmless.
- County Court Judgments (CCJs) and defaults: These carry significant weight and typically stay on file for six years, though how heavily they count varies hugely by lender, size, and how long ago it was.
What's actually worth fixing before you apply
- Register on the electoral roll at your current address if you haven't already — it's free, takes minutes online, and directly helps lenders verify you.
- Check all three credit reports (Experian, Equifax, TransUnion) for errors — a wrongly recorded late payment or an old address still listed as linked to you can drag your file down for no good reason. Dispute anything inaccurate directly with the agency.
- Pay down credit card balances where you can, particularly if you're regularly close to your limit — utilisation matters more than most people expect.
- Stop applying for new credit in the 3–6 months before a mortgage application — new cards, "buy now pay later" plans and even mobile contract upgrades all leave a footprint.
- Close old, unused accounts carefully — closing very old accounts can sometimes shorten your average credit history, so this one is genuinely "it depends"; when in doubt leave dormant accounts open rather than closing several at once right before applying.
- Get on top of any joint finances — a "financial association" with an ex-partner or old flatmate (from a joint account or joint tenancy) can drag their credit history into your file. A "notice of disassociation" with the credit agencies can remove this link once the joint financial tie has genuinely ended.
Making several mortgage-in-principle applications with different lenders in quick succession, hoping one says yes, can itself hurt your file if they're run as hard searches. Many "eligibility checkers" (including Kivo's) use soft searches that don't affect your score at all — worth checking before you apply anywhere that it's a soft, not hard, search.
If you're self-employed or have irregular income
Your credit file matters just as much, but lenders will also weigh income verification more heavily — typically wanting two to three years of accounts or tax returns (SA302s), since your credit history alone won't tell them what a salaried applicant's payslips would. This doesn't make approval harder in principle, but it does mean the paperwork side needs more preparation time.