Bowling Score Calculator

A strike (X) is worth 10 pins plus the total pins knocked down on your next two balls. So a strike followed by a 7 and a 3 in the next frame scores 10 + 7 + 3 = 20 for that strike frame. This is why three strikes in a row (a 'turkey') give you 30 points for the first frame, the maximum any single frame can contribute. Strikes thrown in the 10th frame don't carry forward; the bonus balls are thrown immediately in the 10th frame itself.

A spare (shown as / in scoresheet notation) is 10 pins plus the next single ball, while a strike adds the next two balls. So 5/ followed by a 7 in the next frame is 10 + 7 = 17, but X followed by 7 + 3 is 10 + 10 = 20. The strike bonus is roughly twice as valuable as the spare bonus, which is why pro bowlers chase strikes even when a spare is the safer shot.

Frames 1 through 9 end as soon as you either knock down all 10 pins (a strike, 1 ball) or finish both balls (an open frame or spare, 2 balls). The 10th frame settles strike and spare bonuses inside itself, so if you strike or spare on the 10th, you get a bonus ball (or two for a strike) right there. That's why a perfect game needs 12 strikes (one for frames 1-9, then three more in the 10th), not 10.

A perfect game is 300, achieved with 12 consecutive strikes (10 frame strikes + 2 bonus strikes in the 10th). The USBC certifies thousands of perfect games per season at the amateur level, but they're still rare enough that televised PBA tournaments treat each 300 as a highlight moment. A more practical benchmark: most league bowlers' lifetime best falls between 220 and 280.

X is a strike (all 10 pins on the first ball). / is a spare (10 pins across both balls of the frame). - is a gutter or missed ball (0 pins). So 7/ means 7 on the first ball, spare on the second (3 pins). X X 9 in the 10th frame is a strike, another strike, then 9 pins on the final bonus ball, scoring 10 + 10 + 9 = 29 for the 10th. This notation comes from official USBC scoresheets and works the same in every bowling app.