Downloads are vanity, revenue is math. Paid installs, in-app purchases and ads each feed the model — and the store's 15–30% cut comes off the top before you see a cent.
Paid, IAP and ads modeled separately so you see which one carries the app.
The 30% (or 15% for small business) cut hits app sales and IAP — not ads.
Display eCPM varies wildly by geography and format — 2–10 is a normal range.
All calculations run locally in your browser. Nothing is sent anywhere.
Digital products and apps share the same revenue math.