Guides · Money foundations
The 30% Rule Is a Myth (Sort Of)
Everyone repeats it: keep utilization under 30%. FICO's own analysts say there's no magic number. The rule of thumb is directionally right and specifically wrong, and the difference matters.
Utilization, and the number everyone repeats
Utilization is simply your balance divided by your credit limit. $2,500 against a $10,000 limit is 25%.
The universal advice is to keep it under 30%. FICO's own analysts have said there's no magic number and no cliff — utilization is a continuous factor, and lower is simply better all the way down. People with the highest scores tend to average in the single digits.
So the rule of thumb is directionally right and specifically wrong. Treating 29% as 'safe' and 31% as 'dangerous' misreads a smooth curve as a threshold.
No cliff at 30%. Lower is better continuously — there's nothing special about that number.
Two ratios, and the date that decides them
There are two utilization figures, and both matter. Overall utilization is total balances across all cards divided by total limits. Per-card utilization is the ratio on each individual card — one maxed-out card can hurt even when your overall ratio looks fine.
The reported figure is usually your statement balance, not your balance on the day you pay. That's why paying before the statement closes can lower reported utilization even if you always pay in full.
And the persistent myth: you do not need to carry a balance to build credit. Paying in full builds credit identically and costs zero interest. Carrying a balance only buys you interest charges.
There is no 30% cliff. Lower utilization is simply better, and people with the highest scores average in the single digits.