How much memory is needed to run a Minecraft Server in 1.6.2? [duplicate]
Solution 1:
Tip: If you want to spare more memory, you may set the -Xms parameter even lower, say:
java -Xms32M -Xmx512M -jar minecraft_server.jar nogui
The parameter controls how much memory is reserved on startup. Your server will start with 32MB RAM and whenever it needs more memory it will allocate some until it reaches the maximum of 512M. However, this will result in a little slowdown whenever the allocation is done.
Source: http://www.minecraftwiki.net/wiki/Tutorials/Setting_up_a_server#Less_than_1GB_free_RAM
Also you can check this website : http://www.canihostaminecraftserver.com/
With this you can have a small idea on how many players you can handle :D
Solution 2:
If I remember correctly it's about 10 MB per expected user. However, it is also assuming that the players will stay somewhat close together, if everyone spreads out then you'll need a signifigantly higher amount of ram.