Google have all the information they need to calculate it, as they give med the stats on daily active users in the statistics page. They also have Number of sales, total income etc etc, for all countries, and country breakdown in the economics page… Why have they not made a option to view this important number and make us figure it out by our self?
ARPDAU = Average Revenue Per Daily Active User (DAU)
It would be great if Google could implement it in their reports, both for total sales, and country wise. They will make more money, as we will. Its a win win.
There are no AU stats in developer console unfortunately, although Google did say on last I/O that they are factoring engagement (usage) into Google Play positioning I guess they only collect some basic statistic about application launches and runtime.
If you develop games then you should integrate Google Play Games service and you’ll get access to detailed player activity and performance statistics (including ARPDAU) otherwise you can integrate Google Analytics (Firebase) and use Ecommerce tracking to monitor sales (combine this with AU tracking and you should be able to calculate derived statistics like ARPDAU).
Note that if you have single IAP to sell full version then ARPDAU is meaningless - this is non-recurring purchase so the only important statistics is conversion (which is available in developer console). You should expect conversion in range 1-2%, 5% is doable if your application enjoys high user engagement (key statistic here is average session duration) and is correctly gated. For best results you have to optimize your paywalls - to do so you absolutely have to integrate some kind of analytics and look for frequently used paths, monitor bounce back and fine tune pay gates base on that (for example it’s good idea to remove paywall with high hit rate and high bounce back because they hurt retention really bad).
Thank you for very good information. Not sure if I understood all of that, but I’ll study it some more. Also, I have a screen/activity where the user can uprade to Premium (ad-free), and yesterday 24.000 impression of that activity/screen. That is about normal. So, on this screen, I present the price ($2.5 to upgrade) and on the bottom of the screen there is a big button that says “Upgrade now”. So, they get to se the price, to make a decision before they click the Upgrade button, and 2.400 do this every day. To my big surprise, on average only 20 go thorough and confirm their action to buy, the rest, I don’t know, but they do not end up buying the Premium. I think they cancel the Confirmation screen, or maybe dont have configured the play account with a visa/mastercard, and there for can not complete the process, and be converted.
So, Of 200.000 daily app users => 24.000 => Opens “Upgrade to premium” activity and is presented the price and benefits of upgrading => 2.400 Click “Yes, I want to upgrade” => And boooom… only 20 successful sales in a day…
What is going on here actually? You have a clue?
I’m not 100 % sure what convertionrate this is, but its far from 1-2% … 20 sales out of 24.000 that opens “Premium upgrade activity” = 0,08% ?
Would be happy to send you (or anyone actually!) a $1000 check if you could help me lift this convertion to 1-2% like I had hoped for before I implemented In-app-billing to remove ads. 
So first of all conversion is calculated as % of users that made purchase, this stat is available directly in developer console, along with cohort analysis (which, in short, offer insight how long it take before user made purchase). Since you have single purchase ARPDAU really doesn’t apply here.
Now from you stats it seems that users trigger upgrade screen accidentally or you drive them via interstitial (popup or similar UI element, if you don’t have interstitial nagging for update you may consider dropping two stage purchase, simply start IAP transaction without intermediate activity) hence 90% bounce ratio, because of that there are some accidental clicks on ‘Upgrade Now’ button as well, so it leaves you with 1% sell-through ratio which is not so bad for ad-free IAP (contrary to popular opinion ad-free offer little to non incentivize to purchase for average user, hence it hardly ever converts well and honestly I use it only to silence whining users).
To get better conversion you have to put some functionality behind paywall. Because your application is live and you have decent DAU I’d advice against locking existing features; add something new and make it available for pro users only, it usually good idea to mark UI elements with some badge (lockpad icon, pro only banner etc., if feature isn’t self-explanatory trial period may be required to familiarize users with new functionality but be extra careful to communicate clearly that this is paid only feature or you will face surge of negative comments and low ratings).