There is no number, and the reason is not secrecy. Rockstar has not announced an online mode for GTA 6 at all - no name, no features, no window - so a session size cannot exist yet.
The only reference point that exists
GTA Online has run at 30 players per session on PS5 and Xbox Series X|S, up from 16 on PS3 and Xbox 360 and 30 on the previous generation. Red Dead Online used 32. Those are the numbers Rockstar has actually shipped.
Why “just make it bigger” is harder than it sounds
Player count in an open world is not a slider. Every additional player in a session multiplies the state that has to be synchronised - vehicles, physics, NPCs, weapon fire - across connections that are not all good. Rockstar has also historically used peer-to-peer session hosting rather than dedicated servers for GTA Online, which caps how far the number can be pushed before the experience degrades for everyone.
- More players means more desync, and GTA’s physics amplify it
- A denser city with working interiors is more expensive to synchronise than Los Santos was
- Session size trades directly against how much of the world stays simulated
What about the numbers circulating online?
Figures like 64, 100 or “hundreds” appear in videos and aggregator articles. None trace back to Rockstar. Some trace back to leaked development builds from years ago, which is a category of information that describes an experiment, not a product.
When there will be an answer
After Rockstar announces the mode, which has not happened. We cover the whole online question on the GTA 6 online page, and our multiplayer answer lays out exactly what has and has not been said.