Pick your server type, mods and player count and get a sensible RAM figure with a clear rationale — plus ready-to-paste Aikar’s flags. It is built to be honest, so it will often recommend less RAM than a host tries to sell you.
Peak players online at once — not your total whitelist.
More RAM does not raise TPS. Minecraft's main game loop is single-thread and CPU-bound. Once the heap comfortably fits the working set, extra gigabytes just sit idle — and oversized heaps can make GC pauses worse. A faster CPU core and a lower view distance help performance; more RAM does not.
G1GC tuning by Aikar with -Xmx/-Xms pinned to 2 GB. Paste into your start script.
There is no single answer, but the working ranges are well understood. A Vanilla or Paper server for a few friends is happy on 1–2 GB. A plugin server usually wants 2–4 GB. Light modpacks land around 3–6 GB, and only heavy, kitchen-sink packs with 150+ mods genuinely need 6 GB or more. This Minecraft server RAM calculator starts from those bases, adds a small increment per concurrent player, and weights modded setups by mod count and view distance.
This is the part hosts rarely mention. Minecraft’s main game loop runs on a single thread and is CPU-bound. Once the heap comfortably holds your world’s working set, adding more gigabytes does nothing for tick rate (TPS) — and an oversized heap can actually lengthen garbage-collection pauses. If your server is lagging, a faster CPU core, fewer entities, and a lower view distance will help far more than buying memory.
Aikar’s flags are the community-standard G1GC tuning for Minecraft servers. The
calculator pins both -Xmx and -Xms to your recommended
figure (Aikar advises setting them equal) and adjusts the G1 region settings once you
cross 12 GB. Copy the line straight into your start script and you are done.
Want the full reasoning, edge cases, and tuning advice? Read our guide on how much RAM a Minecraft server needs.
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