Credit Utilisation Explained: The 30% Rule and Your Credit Score
A plain-English guide to what credit utilisation is, how the maths works, why the 30% rule matters for your credit…
Your credit utilisation is how much of your available credit you are using - and it is one of the biggest factors in your credit score. This calculator adds up the limits and balances across your cards, works out your ratio, and shows how much to pay down to reach the levels lenders prefer.
Add each card's limit and current balance - your utilisation updates as you type.
Overall credit utilisation
| Card | Balance | Limit | Utilisation |
|---|---|---|---|
Lenders look at both your overall utilisation and your highest single card, so keeping every card below 30% helps.
| Balance / Limit | Utilisation | |
|---|---|---|
The credit utilisation calculator above shows you exactly what percentage of your available credit you are currently using, in seconds. It takes the balances on your credit cards and revolving accounts, compares them against your credit limits, and returns your credit utilisation ratio as a single, clear figure. Because this number is one of the biggest movable factors in your credit score, knowing it (and being able to test changes before you make them) puts you firmly in control.
This tool answers one practical question: how much of your borrowing headroom are you actually using right now? Lenders and credit reference agencies pay close attention to this because someone who routinely maxes out their cards looks riskier than someone who keeps plenty of room spare, even if both people pay on time.
Specifically, the calculator gives you:
It is a planning tool. You can enter hypothetical numbers, for example a balance after a planned payment, to see how a repayment would shift your ratio before you commit a single penny. Unlike simply glancing at one card balance, the calculator does the awkward arithmetic of combining several accounts with different limits, which is where most people lose track of where they really stand.
You only need two pieces of information per account: the balance and the credit limit. Both appear on your statement or in your banking app.
Tip: include your full limit even on cards you rarely use. An unused card with a healthy limit actually helps your overall ratio, because it adds available credit without adding any balance.
The maths behind your credit utilisation ratio is straightforward:
Utilisation (%) = (Balance ÷ Credit limit) × 100
So a £500 balance on a card with a £2,000 limit gives (500 ÷ 2,000) × 100 = 25%.
There are two ways to look at this, and both matter:
The calculator works out both so you are not caught out by a card that looks fine in the average but is maxed in isolation.
Include every account where you have a credit limit you can draw down and repay repeatedly: credit cards, store cards and charge cards. Some people also factor in an arranged overdraft, treating the agreed limit as the ‘credit limit’ and the amount used as the ‘balance’. What you should not include are fixed-term products such as personal loans, hire purchase, mortgages or car finance — these have no revolving limit, so they do not form part of a utilisation calculation. Keeping the inputs consistent is what makes the percentage meaningful.
The widely quoted 30% rule says you should aim to keep utilisation below 30% of your available credit. It is a sensible ceiling, but it is a floor for safety rather than a target to aspire to. The lowest risk profiles tend to sit in single digits. Keeping a small balance showing (rather than exactly zero) can also demonstrate active, responsible use.
| Utilisation band | Rating | What it signals |
|---|---|---|
| 0% – 10% | Excellent | Ideal range; strong signal of low-risk borrowing. |
| 11% – 30% | Good | Comfortable and within the classic 30% rule. |
| 31% – 50% | Fair | Noticeable; may start to weigh on your score. |
| 51% – 75% | High | Lenders see elevated reliance on credit. |
| 76% – 100% | Very high | Cards near or at the limit; significant red flag. |
These bands are guidance, not hard cut-offs — different lenders and scoring models weight the number differently. As a rule of thumb: under 30% is good, and under 10% is ideal.
Imagine you hold three cards:
Total balances are £1,100 and total limits are £6,000. Your overall utilisation is (1,100 ÷ 6,000) × 100 = 18.3% — comfortably in the ‘good’ band.
Now suppose you pay £600 off Card A. Its balance drops to £300 (10% per-card) and your total balances fall to £500. Your overall ratio becomes (500 ÷ 6,000) × 100 = 8.3% — now in the ‘excellent’ range. Modelling that exact move in the calculator above takes a few seconds and shows you precisely how much repayment shifts the dial.
Notice something about Card A in the original example: at 30% it sits right on the edge of the ‘good’ band even though your overall figure of 18.3% looks healthy. This is exactly why the per-card view matters. If you only had £600 spare, putting it against Card A (the hottest card) does more for how a cautious lender reads your file than spreading the same £600 thinly across all three. The calculator lets you trial both approaches and compare the results side by side.
Here is the detail that surprises most people: the utilisation lenders see is usually the balance reported on your statement date, not the balance after you pay the bill. Your card issuer typically reports to the credit reference agencies once a month, around the time your statement is generated.
That means you can pay your statement in full every month and still show high utilisation — if you spend heavily and the statement closes before your payment lands. Two practical takeaways:
The calculator reflects whatever balance you enter, so for the most realistic picture, use the balance as it stood (or will stand) on your statement date.
If your result is higher than you would like, here are reliable levers, roughly in order of speed:
A useful habit is to set a personal ceiling well below your limit — many people aim to never let any card pass the 30% mark, then chase single digits over time. Re-running the calculator each month, ideally a day or two before each statement closes, turns this from a vague intention into a number you can actually track.
Once your balances are under control, it is worth seeing how the improvement might ripple through your wider profile with our Credit Score Estimator, and checking how your borrowing sits against your income using the Debt-to-Income Ratio Calculator.
No. The calculation runs from the numbers you type in, purely to show your ratio. It is designed for quick, private ‘what if’ testing, so feel free to experiment with different balances and limits.
No — credit utilisation applies only to revolving credit such as credit cards, store cards and some overdrafts, where you have a limit you can draw against repeatedly. Instalment loans like mortgages and car finance have a fixed term and are measured differently, which is where a debt-to-income view is more useful.
It can. Some lenders look at the worst individual card as well as the average, so a single account near its limit may still count against you. Use the per-card breakdown to even things out where you can.
Want the full background on why this number carries so much weight and how the agencies treat it? Read our complete guide, Credit Utilisation Explained.
This tool is general information, not personal financial advice.
Credit utilisation is the proportion of your available credit that you are using, and it is one of the largest single factors in a credit score. This totals your balances against your limits to show where you stand.
The number to aim for is under 30%, and ideally under 10%. The important subtlety is timing: lenders report your balance on the statement date, not after you have paid it off. Someone who clears their card in full every month can still show high utilisation if the reported balance is taken before payment — paying down before the statement date fixes it.
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