The only utilization number that matters is zero. To the best of my knowledge, there is no other verified cutoff that carries any particular importance. As a general rule, a lower utilization is better; keep a small balance on one card and the rest at zero (pay down the balance before the statement date). When that is said, my current Experian FICO score is based on a credit report that has a positive balance on two cards and has a double-digit overall utilization.