In snooker a century break refers to scoring 100 points or more within one visit at the table, without missing a shot. The player does this by potting red balls and coloured balls alternately. Scoring 100 points over the course of a whole frame is not a century, as it must be done during one turn at the table (although you can have more than one turn). Points for a foul shot by the opponent do not count in a player's break.

The highest possible century in snooker is 147 (a "maximum break"), composed of 15 reds, 15 blacks and the six remaining colours; yellow, green, brown, blue, pink and black potted consecutively. Under exceptional circumstances, it is possible to score a break of 155. Should a player come to the table after a foul shot by the opponent and is unable to hit both sides of any red ball, he may nominate one of the colours as a red. Under these circumstances, it is possible to pot 16 reds and blacks, plus 27 points for the six remaining colours, totalling 155 points.

To score a century, there must be at least ten reds (or nine in a free ball situation) on the table when the player comes to play. If there are nine reds, then the most points that can be scored is 99 (= 9 x 8 + 27).