Tools / Minecraft
Minecraft Server RAM & JVM Flags Calculator
Pick your player count and server type and get a recommended -Xmx plus a ready-to-paste startup command using Aikar's tuned G1GC flags - the community-standard config for smooth, lag-free Paper and modded servers. Runs in your browser.
Recommended allocation: 6 GB
Startup command (Aikar's flags - ):
How the estimate works
RAM scales with what the server has to keep loaded: the world, the render/view distance, your plugins or mods, and the number of players. The calculator starts from a base for your server type, adds a per-player amount, and bumps it for a high view distance, then rounds to a sensible heap size. Treat it as a strong starting point, then watch your server's actual memory and timings and adjust.
The generated command uses Aikar's flags - the widely-recommended G1 garbage-collector tuning that keeps pause times low - and sets -Xms equal to -Xmx with AlwaysPreTouch so the heap is reserved up front. At 12GB and above it switches to the large-heap variant of the flags automatically. Always leave RAM for the OS: allocate at most ~75% of the machine's total, never all of it.
Right-sizing a server you actually rent?
Picking a plan is exactly this calculation - RAM for the world, the mods, and the players. The tool is free and needs no account; if you want a host where the plan tiers line up with these numbers, Supercraft is one option among many. See also our modpack sizing guide.