Facebook: How Many Paying Players Can You Expect?
How many players will pay for your game? Between 1–3 percent is typical, whereas 5–9 percent is very good. Among your paying players, about 10 percent are generally whales, paying more than $20/month. A well-designed, well-monetized Facebook game will earn 50 cents to 1 dollar in ARPU per monthly player.
See Chapter 3, “Facebook Games: The Users, the Money, and the Major Players,” for more information.