The amount of RAM a server should have available has been a hot topic since multiplayer first arrived, and here at VAHosting we'd like to rectify a few misconceptions to ensure our server owners get the most out of their server packages.
"How much RAM do I need to run _______?"
First of all, it's important to note that the sheer quantity of RAM is entirely subjective, but rather the way it's utilized is what's most important. For example, a standard Vanilla server will typically utilize much less RAM than the likes of a Spigot / Paper server, however, the same Spigot server can make much better use of the RAM through better optimization and configuration.
"How much RAM do I need for X amount of players?"
Again, it's entirely subjective. There is no specific value you should be looking for when it comes to RAM, however the general consensus is roughly 1GB per 20 players or so, to allow your server the space to breathe should it be needed.
The amount of RAM needed also depends on the version of Minecraft you are running, Minecraft versions below versions 1.8 can run on 1GB of RAM , Minecraft versions above 1.8 need at least 2GB of RAM, and Minecraft versions above 1.13 3GB of RAM or more is recommended.
You will also keep an eye on your servers Memory usage, if it is constantly at 100%, you will need to upgrade the RAM for that server, you can upgrade or downgrade the RAM at any time through your billing area.