Updated 30 October 2026
Starting points for vanilla, plugins and modpacks, why more is not always better, and how to tell when you are actually short.
Most small servers need 2 GB. Around 10 players or a few plugins needs 3 to 4 GB, and modpacks need 4 to 8 GB depending on how big they are.
Memory use depends far more on what the server is doing than on how many people are online, so treat these as starting points: start here, watch the server, and adjust.
Modpacks are the main exception to "it depends on players". Every mod is loaded into memory whether anyone uses it or not, so a big pack needs a lot of memory even with one person online.
The number you set for a Minecraft server is usually the heap: the memory Java may use for the world, players and everything in them. Java also needs memory outside that for loaded mod code, threads and network buffers. On a big modpack that extra can be a gigabyte or more. If a host gives you exactly the number you picked and nothing on top, the server can be killed for using more than it is allowed even though the heap was not full.
Memory the server does not need does nothing for it. A very large heap can even make things worse: Java cleans up unused memory in batches, and a bigger heap means bigger batches and longer pauses. If your server has 16 GB and uses 5, it will not run any faster than with 7.
If the server lags but memory looks fine, memory is not the problem. The usual causes are a high view or simulation distance, large farms with lots of mobs or items, or a single slow mod or plugin. Check the TPS (ticks per second): 20 means the server is keeping up, and anything lower means it is not.
On LunaHost, the memory on your plan is the heap, and the extra Java needs is added on top for you: at least 1 GB, or a fifth of the heap on bigger servers. The panel shows memory and TPS live on your server's Overview, and warns you when a modpack you are about to install usually needs more memory than you have.
See the plans