Craps is fundamentally a game of dice probability. When two standard six-sided dice are rolled, there are 36 possible combinations. Understanding these combinations is crucial to grasping why certain outcomes have specific odds and why the house maintains an edge.
The most likely roll is seven, which has six ways to occur: 1-6, 2-5, 3-4, 4-3, 5-2, and 6-1. This 16.67% probability is why seven is so significant in craps betting. The least likely outcomes are two (snake eyes) and twelve (boxcars), each with only one combination, representing just 2.78% probability each.
Understanding throw probabilities directly impacts betting strategy. The point numbers (4, 5, 6, 8, 9, 10) have varying probabilities that affect payoff odds. For example, four and ten are the hardest point numbers to roll, occurring in only three ways each, while six and eight have five ways each, making them statistically more likely to occur before a seven.
Professional craps players recognize that the come-out roll determines the game's direction. A natural (7 or 11) wins immediately for pass line bettors, while craps (2, 3, or 12) loses. Understanding these probability distributions allows players to recognize which bets carry lower house edges and which should be avoided.
The mathematics of compound rolls—when players attempt to roll specific point numbers before seven—demonstrates why house edge varies by bet type. Some bets like pass/don't pass offer around 1.4% house edge, while proposition bets in the middle of the table can exceed 10% house edge. Informed players use probability knowledge to choose more favorable wagering options.