Dear Liz: I have a 780 credit score but noted that one of my cards doesn’t count in the percent of credit used. I have had this card for 44 years and I could charge a couple hundred thousand dollars on a single purchase if I chose to, yet credit scoring formulas don’t figure in the “credit I have available” from Amex. Seems unfair?
Answer: As credit cards with six-figure limits are rare, what you’re describing is probably a charge card. Unlike credit cards, charge cards don’t have preset spending limits. They also don’t allow you to carry a balance from month to month, typically.
The “percent of credit used” you mention is called credit utilization, and it’s a large factor in credit scoring formulas. Credit utilization measures how much of your available credit you’re using, and the bigger the gap between your credit limits and your balances, the better.
But the credit utilization calculation can’t be made if one of the numbers — the credit limit — is missing. The only way the formulas would be able to calculate credit utilization in that case would be to assume that whatever amount you charged is equal to your credit limit, and that would be disastrous for your scores.