Credit utilisation explained

If you could change one number to change your credit score by next month, it would be utilisation: the share of your available credit that your balances represent. It moves faster than anything else in the file, and almost nobody understands the mechanics. They are simple.

What the ratio is

Utilisation = total card balances ÷ total card limits, computed per card and across the file. A £300 balance on a £3,000 limit is 10%; the same £300 on a £600 limit is 50%. Scoring models treat the ratio as a live risk signal: people maxing their cards are, statistically, closer to financial stress than people coasting at low balances. The general shape of what scoring models measure is in the CFPB's credit score explainer and Wikipedia's credit score entry.

The thresholds, honestly

You will read everywhere that 30% is the magic line. It is a rule of thumb, not a threshold inside the models — scoring is continuous, and lower is better all the way down. The practical shape: keeping reported balances under roughly 30% avoids the worst effects; under 10% is where the strongest scores live; and 0% reported everywhere is slightly worse than a small, paid-as-agreed balance, because the models like to see the instrument actually used. The statement date is the hidden lever: most issuers report your balance on the statement date, not the due date — so paying before the statement closes lowers the number the bureau sees.

The two levers

There are exactly two ways to change the ratio: shrink the balances or widen the limits. Shrinking balances is the healthy lever — paying early (before the statement date), paying more than the minimum, and moving a recurring charge off a near-maxed card. Widening limits works too: the same balance against a bigger limit is a lower ratio. But limit increases can trigger a hard credit check with some issuers — ask first, and prefer soft-checked pre-approvals. Never close a long-standing card to “tidy up”: closing reduces total limits (raising utilisation) and shortens average account age at the same time.

The habits that keep it clean

Three habits cover it. Set a balance alert at 20% of your largest limit — early enough to act. Pay in two beats each month (a partial payment before the statement closes, the rest by the due date) if you want the reported balance low while still using the card. And spread recurring charges rather than stacking them on one card, so no single issuer's ratio spikes. Utilisation has no memory — next month's number overwrites this one — which makes it the most forgiving and most controllable input in the entire file.

Individual cards and the whole file

A low overall ratio can hide one card that is nearly maxed out, and some scoring models consider both the combined figure and individual accounts. Conversely, paying every card to zero just before the statement closes may leave no reported activity at all. The reporting date is controlled by the issuer, so check your credit report after a cycle to see what actually appeared. There is no universal score threshold at exactly 30%; different models, lenders and countries can react differently, and the ratio is only one part of a broader file.

Keep the ratio from becoming a cash-flow problem

Utilisation is not a reason to borrow more or move essential bills onto a card you cannot clear. If balances are growing because income cannot cover expenses, focus first on a realistic repayment plan and avoid adding new credit to cosmetically improve a score. A higher limit can reduce the percentage on paper, but it does not reduce the debt itself and may encourage more spending. The durable improvement comes from balances falling while limits remain stable, with on-time payments and no unnecessary applications alongside it.

Sources and further reading

Links were reviewed 2026-09-29. Regulatory permissions, firm status and product terms can change; use the current official register before acting.

Credit utilisation, explained