the gizmo to the right notwithstanding, what if you are usure as to whether a card will accept or reject your app? since it is used against you to apply too much, how do you know if a particular card will accept or reject you? I wish I could "hypothetically" apply, so the rejection does not effect my credit
There is no straightfoward answer to this question. This forum, and other sites have tried to create a collective database of approval criteria, but it is always in the hands of the credit grantor. I have found that calling and asking what the usual acceptance criteria is will get a good answer. Obvious key factors are income, credit history and score, and employment. A significant part of good credit management is "apply only when you need it". Is there a paticular card you're targeting? Many of the forum members know the general criteria for certain cards.
As Bizwiz said, the only way to really know is to apply. I've seen cases where people with good scores were declined while people with lower scores were approved. A lot of things go into the decision-making process besides scores (like income, as Biz mentioned). There are also many variants of the credit score, and you never know if they are using the true FICO score or a different scoring model.