Deal or No Deal is played in many different ways around the world. Many different countries have their own version or versions of the show, each with their own twists on the same general format. The general format is described here.

The central game of Deal or No Deal involves a contestant, a banker (unseen in some versions of the show), and a host/presenter who acts as Master of ceremonies for the game. The game revolves around the opening of a set of numbered briefcases, each of which contains a different prize (cash or otherwise). The contents of all of the cases are known at the start of the game, but the specific location of any prize is unknown. The value of each of the cases is indicated by a label or card sealed within it.

The contestant claims (or is assigned) a case to begin the game. The case's value is not revealed until the conclusion of the game.

The contestant then begins choosing cases to be removed from play. The amount inside each choice is immediately revealed; by process of elimination, the amount revealed cannot be inside the player's chosen case. Throughout the game, after a predetermined number of cases have been opened, the banker offers the contestant an amount of money and/or prizes to quit the game, the offer based roughly on the amounts remaining in play and the contestant's demeanor. The player then answers the titular question, choosing:

* "Deal", accepting the offer presented and ending the game, or
* "No Deal", rejecting the offer and continuing the game.