Roll three balls per frame and record the score. Like traditional bowling, all pins down in one ball equals a strike and two balls equals a spare, but using all three balls to knock down the pins results in a 10 with no additional bonus balls.
Record the frame at the conclusion of the turn. If a strike, count the next two balls rolled for both the frame the ball was thrown in and the frame with the strike. For a spare, count the next ball thrown for both the frame the ball was thrown in and the frame with the spare. The maximum amount of pins counted toward any frame is 30, accumulated by three consecutive strikes (initial strike plus two bonus balls).
Discount any pins knocked down by balls thrown into the gutter. Occasionally a ball will enter the gutter and return to the alley or come in contact with deadwood in the gutter and knock down pins in the alley. In both these instances, any pins knocked down are disregarded from the total score.
Add the totals from all 10 frames to determine the score for the game. If a bowler rolls a strike or spare in the 10th frame, that bowler must roll additional bonus balls to complete the game. A strike awards the bowler two additional balls and a spare awards a bowler one additional ball. A bowler cannot earn additional bonus balls on top of the bonus balls rolled in the 10th frame.
Add the totals from each game to determine string totals. In candlepin bowling, each game is referred to as a string. Oftentimes, totals are calculated by a single string, three strings, five strings or even 20 strings. The calculation depends on the tournament format.