What should I set -Xmx to?

On Play Your Way you don't set it: every start sizes the Java heap to your plan and locks it, along with Aikar's flags. Java also uses memory outside its heap, so 10% of the plan stays free, at least 512 MB and at most 1.5 GB, and a 4 GB plan runs with a maximum heap of 3.5 GB. On another host, leave the same gap below the plan's memory, or the server can be stopped for going over its limit.

Why does view distance change RAM so much?

Each player keeps the chunks around them loaded, roughly (2 x view distance + 1) squared of them, and a loaded chunk costs memory whoever is standing in it. Ten players spread out at the default view distance of 10 hold over 4,000 chunks; at 8 they hold under 3,000. Lowering it is the cheapest way to fit more players in the same RAM, and the guide to how much RAM a Minecraft server needs has the full table.

How much RAM does a modded server need?

Mods load before anyone joins, so a modded server starts higher and climbs faster per player. By the calculator's maths, five players need 1 GB on Paper, 3 GB on Fabric with 20 to 40 mods and 10 GB on Forge with 80 to 150. For a one-click modpack, start from the RAM it is set up with in the list above.

Can I change my RAM later?

Yes. In Billing, choose Change plan on the server's subscription and pick a bigger plan, or add Additional RAM to the one you have. An upgrade is charged today, prorated for the days left in the billing period, and the new RAM takes effect when the server next starts; a cheaper plan starts at your next renewal. Your world, files and settings stay as they are, and the plan change guide walks through every step.

Minecraft server RAM calculator

Players, software and mod count in - a memory recommendation out. The maths is the same sizing we use when we build a server, and it works for any host, not just ours.

For the reasoning behind the numbers and the signs a server is short on memory, read how much RAM a Minecraft server needs.

1Player count

How many concurrent players?10

2Server software

Server type

Paper / Purpur run plugins (lightweight). Fabric / Forge / NeoForge run mods (heavier).

How much RAM does a Minecraft server need?

A small vanilla or Paper world runs in 2 GB. A player’s own data is only 50-75 MB, but the chunks they load cost more, so the calculator budgets up to 5 players per GB on vanilla or Paper and 2 with mods, the rule our plan cards use. Mods also add to the base, so a modpack needs more memory for two players than a plain server needs for thirty. The table shows the most players each size holds by the calculator’s own maths, 25% headroom included.

Most players each amount of RAM holds, by server software
RAM	Vanilla	Paper	Fabric, 20-40 mods	Forge, 40-80 mods
2 GB	10	10	Too small	Too small
4 GB	20	20	8	Too small
6 GB	30	30	12	Too small
8 GB	40	40	16	16
10 GB	50	50	20	20
12 GB	60	60	24	24

View distance, plugins and busy farms move these numbers, so check your own setup in the calculator above.

How much RAM does a modpack need?

What we set each one-click modpack up with for a small group, sized for that pack’s own mods rather than by the general estimate in the table. Add memory as the player count grows.

RLCraft6 GB (Forge)
All the Mods 1010 GB (NeoForge)
All the Mods 910 GB (Forge)
Better MC8 GB (Forge)
Cobblemon6 GB (Fabric)
Pixelmon6 GB (NeoForge)
Vault Hunters 3rd Edition8 GB (Forge)
Create: Above and Beyond6 GB (Forge)
DawnCraft8 GB (Forge)
Prominence II RPG6 GB (Fabric)
Fabulously Optimized4 GB (Fabric)
SkyFactory 46 GB (Forge)

FAQ

Free toolMinecraft Seed MapBiomes, structures, slime chunks and spawn for any Java seed, in every dimension, before you load it. 1.19 to 26.2.
Free toolMinecraft Nether Portal CalculatorOverworld to Nether and back: the spot to build at, the tp command to get there, and whether two portals you already have will link.
Free toolMinecraft /give Command GeneratorAny of 1,536 items or a ready-made potion or book, with enchantments at any level, a custom name, lore and Unbreakable, written the way your version needs.
Free toolMinecraft server properties generatorEvery setting as a labeled control with its default, or paste your own file in to edit it. Copy a ready server.properties out.
Free toolMinecraft MOTD GeneratorType two lines, color and style them, see them in the game's own font, and copy them ready for your server.
Free toolMinecraft Aikar's flags generatorYour server's RAM in, the tuned G1GC startup line out: the flags Paper recommends, sized for the heap you have.
GuideWhy is my server lagging? Find the cause
HostingMinecraft server hosting

Free to use and share. Link to this tool from your guide, wiki or Discord.

One-click modpacks

Preinstalled and sized to the right plan. Pick one, we deploy it.