Friday, April 22, 2011

Estimate the sales of any app

While I was developing River of News I looked around for any discussion I could find where developers revealed their sales or the relation of ratings to sales. I found several sources independently say that about 1 in 30 buyers of a paid app will rate it in the store. I now have two apps in the store and that ratio has held up remarkably well.

I'm sure there are exceptions and my information is far from comprehensive, but I have enough evidence to believe that multiplying the number of ratings in the U.S. App Store by 30 will give you a ballpark estimate of the sales of an app.

I'm curious to hear from other developers if this ratio is accurate for their products.


  1. I'm the developer for Capparsa's apps and for whatever reason, my sale/review ratio is terrible. For ex, TimeTag Free has been downloaded 16,423 times but it's only got 15 ratings (not even all reviews.)

    The paid version has 41 ratings, but has several thousand downloads.

    It might just depend on the type of app? I even have a "rate this app" link the app, which didn't really seem to help.

    The other (unfortunate) thing I've found is that if you ever have some kind of show-stopping bug in the app, nobody hesitates to leave a 1 star review, so the ratio goes up, but obviously not in your favor...

  2. You should add something asking people to rate your app - its relatively unobtrusive and our number of ratings rose dramatically after including it in a new update. Check out Appirater - its what we use in Drop Dead (

  3. Taptaptap releases public numbers on their blog. Camera+ has over 1.8M paid downloads, only ~7800 ratings. Less than a 1/2 of 1 percent. This seems to hold true with most apps I've seen.

  4. I think the 30X multiplier is too low at least if the app is popular. Camera+ is a good example since they have published #'s. It's more like 1 in 300 to 500 for them. My own #'s are closer to Camera+ than to the 30X. We have a popular app also but not as popular as Camera+

  5. I don't think this works. Although I wish it did.

    Reason #1: Some apps encourage reviews with nags and links.

    Reason #2: At a lower level of reviews, it is likely that a developer had all his friends review the app.

    Reason #3: When apps are offensively terrible, people are more inclined to visit the app store and 'vent'.

  6. I just checked re: one of my new apps.

    12 ratings
    5 reviews
    860 purchases

    So.... x30 doesn't seem right at least in this case...

  7. I released my new iPhone app, KEYBOX ( ) just over a week ago and I only have 2 reviews so far. At least they're glowing reviews.

    Sales come and go in waves and perhaps because the lite edition of the app does 100% of the what the full edition does (only for 30 days mind you) it's too early to say if I'll have the same ratio as you once all the lite edition users to upgrade or not.

    In any case, I have close to 300 downloaders of KEYBOX lite so my review to download ratio is about 2/300.

  8. Ran across this post while searching for a similar one I’d seen before (maybe in a BoardGameGeek forum?).

    For King of Dragon Pass, we’ve got 492 stars and over 25000 sales. So it’s off, but at least within an order of magnitude. (Another non-free game I know sales for it is also within an order of magnitude.)

    (I don’t think this technique works for something that isn’t in the charts. But

  9. I have around 5 apps in AppStore and the ratio is different for each one. Two of them have around 200 downloads for every 1 rating whereas one of them gets more than 100 downloads everyday but no rating for several months ! The ratio is over 10000:1 for this app. Even for one of them app that now obeys roughly 200:1 ratio, it was close to 1000:1 before the update which had better features and prompts the user to rate the app.