Ask ten people what a 'bad' credit score is and you'll get ten different numbers. That's because the score isn't the thing lenders actually check. Here's what really counts, and how to read your file the way an underwriter would.

What is a bad credit score?

Each UK bureau uses its own scale — Experian tops out at 999, Equifax at 1,000, TransUnion at 710. A number below the middle of any of those ranges typically triggers extra scrutiny, but the score itself is only a signal. What lenders read is the underlying file: missed payments in the last 24 months, active defaults, CCJs, and how much of your available credit you're currently using.

The three UK bureaus explained

Experian, Equifax and TransUnion each hold a slightly different picture of you. Some lenders report to only one; others report to all three. That's why your Experian file can look healthy while your TransUnion file shows a missed direct debit from 2023. Check all three at least once a year — Credit Karma (TransUnion), ClearScore (Equifax) and Experian's free tier are enough.

The score is a mirror, not a verdict. Lenders look through it, not at it.

Why your score changes month to month

Utilisation is the biggest short-term mover. Pay a credit card down before the statement date and your score can jump 40 points overnight. Take a new hard search and it drops 20. Close an old account and the average age of your file falls, which pulls the score down even though nothing 'bad' happened.

How lenders actually decide

Modern affordability-led lenders (including most retail credit and BNPL) barely look at the score. They check three things: (1) can you afford this repayment given your declared income and known outgoings, (2) is there a live default or CCJ, and (3) is the application itself consistent (address history, employment, bank data via Open Banking). A 'thin' file with no defaults often beats a 'fat' file with one missed payment last year.

What to do next

Get on the electoral roll at your current address. Set a direct debit for the minimum payment on every credit line you hold. Bring utilisation under 30% of your limit. Wait 30 days and re-check. That's the entire playbook for the first quarter of any rebuild.

The bottom line

Credit is a long game. Small, consistent moves — on-time payments, low utilisation, and honest paperwork — beat any single silver-bullet product. If you take one thing from this guide, take that.