The maximum break in snooker under normal circumstances is 147. This is often known as a maximum, a 147, or orally a one-four-seven. The 147 is amassed by potting all 15 reds with 15 blacks for 120 points, then all six colours for a further 27 points. The maximum break has been achieved 90 times in professional competition. Ronnie O'Sullivan and Stephen Hendry have compiled 11 official maximum breaks each, the most ever by any professional player. Scores above 147 are possible in the case of free ball due to fouling by the opponent; this has only happened once in a professional tournament.
In six-red snooker, the maximum break is 75 points, as there are fewer reds and thus fewer black-scoring opportunities. In snooker plus the maximum is 210 due to the additional, highpoint-value colours. However this was never achieved due to the distance between the purple ball and the reds.
In professional tournaments there was usually a substantial prize awarded to any player achieving a 147 break. Ronnie O'Sullivan's maximum at the 1997 World Championship earned him £165,000 (£147,000 of this was for making the 147 break and another £18,000 was for achieving the highest break of the tournament). This was however abolished in the 2010/2011 season. In the 2011/2012 season World Snooker introduced a roll-over system for the maximum break prize money. A maximum break is worth £5,000 in the televised stages and £500 in qualifying stages of major ranking events. There is a £500 prize in the Players Tour Championship events from the last 128 onwards. If a maximum is not made then the prize rolls over to the next event until somebody wins it.