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Hi! I'm Chris

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iOS Sale Numbers By App Store Rank

May 8th, 2013

After reading about Choosing a Profitable Niche, I wanted to see how my own iOS app sales matched the numbers Trevor used for his analysis. I only do iOS development as a side project, but have one app: Play Piano HD, which has been on the Top Paid App charts for Music (in the US) for several months now.

The Numbers

I used App Annie to get my approximate ranking on the Music Chart over the past 30 days, and used my download numbers to try to answer the question: "How does app store rank correlate to app downloads?" My first step was to graph sales as a function of app store rank (US Music Category):

You can begin to see the expected exponential curve, but what about the predicted numbers? According to the post, it takes 80 downloads per day to hit the top 25 in the Music category. I don't have data for position 25, but I can plot that point on the graph:

That falls right in line with the premise that app downloads are exponential as a function of rank.


It is generally accepted that app store rank has an exponential correlation with sales, and that can be seen clearly in both graphs. This has important side effects:

App Popularity Is Not Linear

As an example, Angry Birds isn't just a little bit more popular than other games: it is massively more popular. Many apps have viral effects as users recommend the app to other users and review sites and news outlets cover already popular apps - making them even more popular. That leads to a natural exponential curve.

Top 50 Is The Inflection Point

On the graph above, the inflection point from "ok" to "great" is right around the top 50 apps. That wasn't a surprise, as several interfaces to the app store will load the top 50 apps in a category as the default popular apps. That leads to the next result:

App Store Rankings are Self-Enforcing

App discovery is a challenge, and the easiest way for users to find new apps is to look at the apps that are already popular. This leads to a reinforcing effect of app store rankings: popular apps get more downloads because they are already popular, making them even more popular. This makes it very difficult to break into the top 50 ranking for any category.

Getting To The Top Of The Charts

So, how to get past the top 50 inflection point? That's the subject of my next post, but here's a preview: there are no shortcuts (short of dumb luck), but there are ways to increase your chances. In the next post I'll cover app design, keyword tricks, pricing, and more - so stay tuned!

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