How many people play mobile games worldwide?

How to get close to this number

Start from smartphone ownership. There are several billion smartphones in use, and a majority of owners have played something on them — a puzzle game on a commute counts. A high fraction of a multi-billion device base gives a player count in the billions, which is what makes mobile the dominant gaming platform by participation.

The definitional looseness is what inflates it, and it is worth naming. Someone who plays a word game twice a week is counted alongside someone who plays daily for an hour, and the category includes games most players would not describe as games. Broad participation figures always depend on where the threshold is set.

The revenue point in the explanation is the structural one: mobile earns roughly half of all games revenue despite most players spending nothing. A small minority of high-spending players funds the entire platform, which is the same concentration pattern as the streaming and board game questions here — and it is why free-to-play works at all.