How to find the number of downloads for an app in the itunes store?
The number of downloads for a particular application in the iTunes store is not made public by Apple – and most app developers don’t make that information public either due to competitive reasons. So, the best you can do is estimate the number of downloads that an app has on the iTunes store.
According to the academic paper here, there are some formulas you can use to estimate the number of apps that have been downloaded for a given app on a given day – not for the lifetime of the app. But, you need to know the ranking assigned to the app by the iTunes store. There are different formulas for both iPad and iPhone applications.
Formula to find the number of downloads for an iPad app
According to the paper above, a good formula to use to find the number of downloads for an iPad app is this. Now, here’s how to use the formula: simply take the rank to the power of -.903 and multiply by 13,516. Remember that the way a negative exponent works is that you take 1 over the number to the power of the positive value of the exponent. So, 2-1 is 1/(21), which is equal to 1/2 or .5. Here’s the formula:
number of iPad downloads = 13,516 * rank(-0.903)
This means that the second highest ranked iPad application would get 13,516 * 2-.903 downloads per day, which is 7,228 downloads per day.
Formula to find the number of downloads for an iPhone app
And, here’s the formula to use to find the number of downloads for an iPhone app – it’s similar to the one for the iPad, but with different numbers.
number of iPhone downloads = 52,958*rank-(0.944)
This means that the second highest ranked iPhone application would get 52,958 * 2-.944 downloads per day, which is 27,522 downloads per day.
Analytics tools to find the number for an app in the iTunes store
There are also a number of analytic tools – like http://www.appannie.com/, http://www.distimo.com/app-analytics#appiq, and xyologic.com. Of course all of these apps just try to make the best estimate that they can – no one has the exact statistics except Apple and the actual app developers themselves who get reports from Apple about the apps that they are responsible for developing.
If you are curious about how the iTunes store determines the rankings for their apps, then read this article: How does iTunes rank apps?