What Sizes Do Billiard Balls Come In?

Carom (Billiard) Balls

The game of Carom Billiards uses three balls and is played on pocketless billiards tables. Carom balls are not numbered. The regulation size and weight of the balls are as follows:

• between approximately 2³⁄₈ and 2⁷⁄₁₆ in, (61–61.5 mm) in diameter
• weight ranging between 7.2 and 7.8 oz, (205 and 220 grams) with a typical weight of 7.5 oz. (210 g).

They are typically colored as follows:

• White: cue ball for player 1
• White with a spot or solid yellow: cue ball for player 2
• Red (occasionally blue): object ball 

Pool (Pocket Billiard] Balls

Pool balls are used to play various pool games, such as eight-ball, nine-ball, and straight pool. The balls are numbered and colored

The regulation size and weight of the balls are as follows:

• diameter of 2¹⁄₄ in (57 mm), plus or minus 0.005 in (0.127 mm)
• weight may be from 5+¹⁄₂ to 6.0 oz (160–170 g)

Coin-operated pool tables, such as those found at bowling alleys, arcades, or bars, may use a slightly different-sized cue ball, so that the cue ball can be separated from object balls by the table's ball return mechanism and delivered into its own ball return. Such different sized cue balls are considered less than ideal because they change the dynamics of the equipment. Other tables use a system where a magnet pulls a cue ball with a thin layer of metal embedded inside away from the object ball collection chamber and into the cue ball return, allowing the cue ball to more closely match the object balls in size and weight.

Snooker

The regulation size and weight of Snooker balls are as follows:

• diameter is standardized at 2.07 in (52.5 mm) and within a tolerance of plus or minus 0.002 in (0.05 mm).
• However, many sets are actually 2¹⁄₁₆ in (52.4 mm). Snooker sets are also available with considerably smaller-than-regulation balls for play on smaller tables (down to half-size), and are sanctioned for use in some amateur leagues. Sets for American snooker are typically 2¹⁄₈ in (54.0 mm).
• standard weight is not defined, but all balls in the set must be the same weight within a tolerance of 0.11 oz (3g). 

Bumper Pool

Bumper Pool requires four white and four red object balls, and two special balls, one red with a white spot and the other white with red spot; all are usually 2¹⁄₈ inches (54 mm) in diameter.