College students are using credit cards more than ever before, according to a survey of private-student-loan applicants released today by Sallie Mae, the giant student-loan company.

The study examined the credit-bureau reports for a randomly selected group of 1,200 applicants for private student loans. The study also used self-reported information from 249 private-student-loan applicants who responded to a survey.

Eighty-four percent of the students have at least one credit card, compared with 76 percent in 2004, the last year the study was conducted. Part of that increase is probably due to the timing of this year’s study — in the spring instead of the fall — and the larger concentration of juniors and seniors in this year’s sample, according to a report on the study.

Students with credit cards have an average of 4.6 of them, the report says, and half have four or more cards. The median credit-card debt is $1,645.

Ninety-two percent of respondents with credit cards said they had used them to pay for some kind of college expense. Thirty percent said they had used credit cards to pay part of tuition. Only 17 percent of respondents said they paid all of their card balances every month. —Beckie Supiano