# How do you calculate a ten-pin bowling strike rate?

I'm a USBC League Bowler, and I'm tracking my own stats, and I want to know my Strike Rate Percentage.

Theoretically, you would take and divide the number of frames bowled by the number of strikes bowled, but how do you account for the tenth frame? If I bowl a perfect game, that's 100%. But let's take this scenario where I bowled a 232.

As you can see here I have 8 strikes in the game and 2 of them in the tenth frame. 8 strikes / 10 frames is 80% strike rate, but not when 2 of the strikes are in the tenth frame. 8 strikes / 12 first throw chances for 75%.

How do I figure this out in Excel?

Your divisor here isn't "frames", but the number of times you threw at a full rack. So with three full racks in the tenth with your sample game, you're correct that you should divide by 12.

If you don't close out the tenth, then you could be dividing by only 10.

Pseudocode for Excel. I'll indicate the ball number after the frame:

``````if (10.1 == "x" and 10.2 == "x") -> number of racks = 12
elseif (10.1 == "x" or 10.2 == "/") -> number of racks = 11
else -> number of racks = 10
``````
• I admit it's unlikely to happen for anyone throwing strikes on a regular basis, but what happens if you miss entirely with the first ball of a frame - does that count as one or two attempts on a full rack? Sep 16, 2019 at 8:55
• Unfortunately, while I found many sites discussing the concept, I did not find any "official" formula from a sanctioning body like USBC or PBA. So I can't say for sure. From a training point of view, it would make sense to count it as a strike attempt. But from a scoring point of view, it won't be a strike, so it's not one. Personally, I'd count it as only one attempt because the math is easier. Be great if someone can find a description of how official records are calculated. Sep 16, 2019 at 9:02

I calculate my own bowling stats as well but I don't see any game as having a possibility of more than 10 "strikes". Even the bowling software at my local bowling alley doesn't identify the second and third strikes in the 10 frame as strikes. The software identifies them as 10s. So in my opinion a perfect bowling game scoring 300 consists of 10 "strikes" and 2 10-fills. The question above about do you count a a 10-pin spare as a strike? Of course not! It's a spare! And if you missed completely on the first two balls and threw a third ball knocking down all 10 pins then that is just a 10-frame. If you have a mark in all 10 frames, even if you don't have a perfect 300 score, you still have a 100% mark percentage. Can you have a perfect strike % without throwing a 300 game. You just don't have a perfect fill on that last strike in the 10th frame on either the second or third ball.