How do I know how full a server is?

[Kiki-Jiki]

I like to play on servers with a lot of people. . .I may want to transfer.

[Felghanna]

Hum... I don't know if there is any command to see how many players are online, even so you could only see how many players are online in your server... And yet, this may counts the bots too which is not a health calculation.

Anyway if you need help in game, I could do something about it since you are in the same server as I am.

[GenJoe]

http://xivsoul.com/

They keep track of player stats using the lodestone data. It's not a 100% accurate and when it's mid-scan, numbers can be off. But it should give you a general picture.

[Naria]

There is no way in game to see how many people are logged in. The only way we have to judge how popular a server is is how frequently it has character creation or log in restrictions imposed.

Honestly, since the Duty Finder for dungeons etc is cross server anyways, it is likely not to matter until you are at or near the level cap as regardless of server size most people don't chat in the open world but instead in their Free Companies (FC) and Linkshells (LS). If you want lots of people to socialize and play with, I'd suggest finding a large FC and/or LSes. You can have only one Free Company, but several linkshells.

If you don't like your server and want to leave now, I'd just save your character design in the login window and recreate them on another server since you are not very far along, and server transfers cost money.

[Flett117]

Wait, how many people are qeued in front of you? At max I only ever wait a couple minutes. Plus I figure this, the lower the pop the last likely you will get in a dungeon party. Keep that in mind before you transfer.

[Niwashi]

I figure this, the lower the pop the last likely you will get in a dungeon party.

For Duty Finder, it doesn't matter what the population of your server is, since that draws in people from other servers as well.
For forming a party yourself by finding people from your FC and/or linkshells to join you, it's the size and activity of your FC/LS that matters rather than of your server.
But for using Party Finder to form groups, this can be true. High-population servers will generally tend to have more PF activity.