Q: I can pay my tuition bills of a few thousand dollars a year on my American Express card and get “Reward Points,” but it costs 2 percent extra to pay the tuition this way.

A: You get one point for every dollar you put on the card, and over the past year, I’ve accumulated about 5,000 points.

Is this worth the 2 percent fee?

You’re probably not making anything. As a rule of thumb, credit-card rewards are worth 1 percent to 2 percent of the amount charged. So the rewards you accumulate probably are not worth more than the 2 percent fee you must pay the college for using the card.

You’re being charged this fee because the college does not want to pay the fee card issuers charge merchants. The federal government has the same policy for people who use credit to pay tax bills.

Since most ordinary merchants don’t pass these fees on, card users can, indeed, benefit from rewards programs, if they’re careful.

Some cards offer extra reward points based on the balance in the user’s account. This is never a good deal; interest charges on unpaid card debts are certain to cost more than the points are worth.

Also be aware of annual membership fees charged by cards offering points. If you don’t use the card very much, you may not accumulate enough points to justify paying the fee. You’d be better off with a no-fee card.

Generally, rewards programs are best for heavy card users who pay their card bills in full every month.