UK finance jargon - in plain English
A number that reflects how reliably you repay debt.
A credit score is a number used by lenders to assess how likely you are to repay borrowed money. In the UK the main credit reference agencies are Experian, Equifax, and TransUnion. Each uses its own scoring model and scale, so your score will look different depending on which agency you check. Lenders use this information, alongside their own criteria, to decide whether to approve applications and what rate to offer.
You apply for a mortgage. The lender checks your credit file and sees two missed credit card payments from the past year and a high level of existing debt. They either decline the application or offer a higher interest rate to offset the risk. Sorting out your credit file before applying, paying on time, reducing balances, and correcting any errors, can make a meaningful difference to what you're offered.
Numbers simplified for illustration. Actual rates and eligibility criteria vary by lender.
Many people think checking their own credit score damages it. It doesn't. Only hard checks, which are full credit applications where a lender searches your file, leave a mark. Checking your own report is a soft check and has no impact on your score. You can check as often as you like.