RAM Calculator

World size multiplier applied: 1.1x

-Xms4G \
  -Xmx4G \
  -XX:+UseG1GC \
  -XX:+ParallelRefProcEnabled \
  -XX:MaxGCPauseMillis=200 \
  -XX:+UnlockExperimentalVMOptions \
  -XX:+DisableExplicitGC \
  -XX:+AlwaysPreTouch \
  -XX:G1NewSizePercent=30 \
  -XX:G1MaxNewSizePercent=40 \
  -XX:G1HeapRegionSize=8M \
  -XX:G1ReservePercent=20 \
  -XX:G1HeapWastePercent=5 \
  -XX:G1MixedGCCountTarget=4 \
  -XX:InitiatingHeapOccupancyPercent=15 \
  -XX:G1MixedGCLiveThresholdPercent=90 \
  -XX:G1RSetUpdatingPauseTimePercent=5 \
  -XX:SurvivorRatio=32 \
  -XX:+PerfDisableSharedMem \
  -XX:MaxTenuringThreshold=1 \
  -Dusing.aikars.flags=https://mcflags.emc.gs \
  -Daikars.new.flags=true

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The amount of RAM your Minecraft server requires depends on several factors: the server software you run, how many players connect simultaneously, the number of plugins or mods loaded, your world size, and any extra features such as Dynmap or custom terrain generation.

A Vanilla server can start with as little as 1 GB for a handful of friends, while a heavily modded Forge or NeoForge instance with 100+ mods may need 8 GB or more. Paper and Spigot servers are more memory-efficient than Vanilla thanks to performance patches, but every plugin you add increases the footprint.

This calculator estimates both the minimum and the recommended amount of RAM. The recommended value includes a 30% headroom buffer so the garbage collector has room to work without causing lag spikes. It also generates the correct JVM startup flags: Aikar's optimized G1GC flags for allocations under 12 GB, or ZGC flags for larger servers running Java 21+.

Proxy servers like BungeeCord and Velocity are lightweight and only need around 512 MB base plus roughly 15 MB per connected player, since they do not load worlds or run game logic themselves.