Minecraft Server RAM Calculator (Java)
Enter your server type, players and view distance to get a memory estimate and a ready start script. For example, a Paper server for 10 players at view distance 10 should get about 4 GB.
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Give the server
3 GB
- Vanilla server: 2 GB
- 5 players: 0.5 GB
- View distance 10: 0 GB
@echo off title Minecraft server cd /d "%~dp0" :start java -Xms3G -Xmx3G -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 -jar "server.jar" nogui echo Server stopped. Restarting in 10 seconds (close this window to stop)... timeout /t 10 goto start
Put start.bat next to your server jar and double-click it. The first start creates eula.txt: set eula=true to accept Minecraft's EULA, then start again. Next, tune the world with the server.properties generator.
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Rough RAM needs at view distance 10
| Server type | Players | Give the server |
|---|---|---|
| Vanilla | 5 | 3 GB |
| Vanilla | 20 | 4 GB |
| Paper / plugins | 5 | 3 GB |
| Paper / plugins | 20 | 5 GB |
| Few mods | 5 | 5 GB |
| Few mods | 20 | 7 GB |
| Big modpack | 5 | 7 GB |
| Big modpack | 20 | 10 GB |
Estimates from the same rule as the calculator. Big modpacks vary a lot: check the pack's own recommendation too.
How to use it
- Pick your server type: vanilla, Paper with plugins, a few mods or a big modpack.
- Enter how many players are usually online and your view distance.
- Optionally enter how much RAM the machine has, so the estimate leaves room for the system.
- Download start.bat (Windows) or start.sh (Linux, Mac) and put it next to your server jar.
- Run it once, set eula=true in eula.txt to accept Minecraft's EULA, and run it again.
How it works
The estimate is a rule of thumb, not a measurement: a base amount for the server type, a little more for each player, and extra when view distance goes above the default 10, because the loaded area grows with its square. It is rounded up to whole gigabytes and capped so the operating system keeps at least 2 GB or a quarter of the machine. The script starts Java with the same minimum and maximum memory (-Xms and -Xmx) and, if you choose, Aikar's garbage-collection flags, which the PaperMC documentation recommends to reduce lag spikes.
Questions
Is more RAM always better?
No. Past what the server needs, extra memory doesn't help and can make garbage-collection pauses longer. Lag usually comes from the CPU, view distance or a heavy mod or farm.
What are Aikar's flags?
A set of Java garbage-collector settings tuned for Minecraft servers, published by Aikar and recommended by PaperMC. They make memory clean-up smoother so the server stutters less.
Why set -Xms and -Xmx to the same value?
It reserves the server's memory once at start-up, so Java doesn't keep growing and shrinking it while you play. It's the usual advice for dedicated servers.
What does eula=true mean?
The server won't run until you accept the Minecraft EULA. Open eula.txt after the first start, change eula=false to eula=true and save.
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By PickaxeKit Editorial Team. Updated 2026-11-09.