The APR is the headline number on a feature you should hope never to use. For a cardholder who pays in full, it is almost irrelevant; for one who carries a balance, it is everything. The whole question is which kind of cardholder you intend to be.
What the APR is
The APR is the rate at which interest accrues on a balance you carry from one month to the next. Think of it as the price tag on borrowing. It only ever applies when you actually borrow — that is, when you do not pay your statement in full.
Why it's irrelevant if you pay in full
Pay the full statement each month and the price of borrowing simply never comes due. You can hold a card with a high APR and pay none of it, because you never trigger the condition that activates it. For the disciplined payer, the APR is a number watched only by others.
When it suddenly matters a great deal
The moment you carry a balance, the APR stops being scenery and becomes the dominant force on the card — a shift explained in "The grace period explained." From that point, it can outweigh every reward the card offers, and then some.
Don't choose a rewards card on its APR
If the APR is your main concern when choosing a rewards card, that usually signals you expect to carry a balance — in which case a low-rate, no-frills card may serve you far better than any rewards card. Choose the tool that matches your actual habits, not your aspirations.
The honest self-test
Ask yourself plainly whether you will clear the balance in full every month. Answer it honestly before you choose a card. The answer determines whether you are shopping for rewards or for a low cost of borrowing — and those lead to different cards.
For the disciplined, the APR is scenery. For everyone else, it is the whole landscape — which is why honesty about which you are comes first.
