Credit utilisation is the proportion of available revolving credit currently being used, and it is generally among the larger factors in scoring models after payment history.

This describes how it generally works rather than advising on anybody's circumstances.

How it is calculated

Balance divided by limit, expressed as a percentage.

Generally calculated both per account and across all revolving accounts combined, with models weighting each.

The figure used is typically the balance reported to the agency, which is usually the statement balance rather than the balance at any given moment.

Which is the detail that produces most of the confusion.

The statement date effect

Where the timing matters more than the behaviour.

A card paid in full every month can still report a high utilisation, if the statement is generated when the balance is high.

Which means somebody who never carries debt can show high utilisation, and somebody who pays only the minimum on a small balance can show low utilisation.

The reported figure reflects a snapshot rather than a pattern.

Paying before the statement date, rather than by the due date, reduces the reported figure, which is a mechanical consequence rather than a trick.

The thresholds

Frequently quoted and worth treating carefully.

Guidance commonly suggests keeping utilisation below around thirty percent, and lower is generally treated more favourably.

These figures are approximations derived from observed model behaviour rather than published thresholds, since scoring models are proprietary.

What is reasonably established is that the relationship is continuous rather than a cliff — lower is generally better across the range, with the effect strongest at the extremes.

The zero utilisation question

Which is counterintuitive.

Some models appear to treat very low or zero utilisation slightly less favourably than a small positive figure.

The reasoning is that a scoring model predicts repayment behaviour, and an account with no activity provides no evidence of it.

Which means an unused credit line contributes to the available limit and provides no repayment history, and this is one of the less intuitive features of these systems.

Why closing accounts can hurt

A common and consequential mistake.

Closing a credit account removes its limit from the available total, which raises utilisation on the remaining balances.

It can also shorten the average age of accounts, depending on how the model treats closed accounts.

Which means closing an unused card, intending to tidy up, can reduce a score rather than improve it.

The counterweight is that unused accounts carry fraud risk and annual fees, and those are real considerations.

Limit increases

Which affect the ratio from the other direction.

A higher limit with the same balance produces lower utilisation.

Requesting an increase may involve a hard search depending on the lender, and some offer increases without one.

The obvious caution is that a higher limit is only helpful if it does not lead to a higher balance, which is the behavioural risk that makes this advice double-edged.

What matters more

Worth keeping in proportion.

Payment history is generally weighted more heavily than utilisation in most models, and a missed payment does considerably more damage than high utilisation.

Which means the ordering of priorities is to pay on time, always, and then to manage utilisation.

Automatic minimum payments as a backstop, with larger payments made manually, is a common arrangement that addresses the first priority without relying on memory.

The wider caution

A score is a means rather than an end.

Optimising a number is only useful if it produces access to credit on better terms, and the value of that depends entirely on whether the credit is needed.

Which is worth stating because there is a substantial amount of content encouraging score optimisation as an activity in itself, and for somebody with no borrowing plans it achieves very little.

Instalment credit is treated differently

A distinction worth making since the term utilisation is applied loosely.

Revolving credit — cards and overdrafts — has a limit and a fluctuating balance, which is what utilisation measures.

Instalment credit — loans, finance agreements — has a fixed balance reducing on a schedule, and is generally treated differently by scoring models.

Which means a large loan balance does not affect utilisation in the way a large card balance does, though it appears in overall indebtedness measures that lenders assess separately.

Overdrafts

Treated differently between systems and worth checking.

An arranged overdraft is a form of revolving credit and may be reported with a limit and a balance, in which case usage affects utilisation.

Reporting practice varies by jurisdiction and by provider, and some report only when the facility is used.

Which means a permanently used overdraft can contribute to utilisation in a way people do not associate with a credit facility, since it feels like part of the current account rather than borrowing.