Undertale Server: RAM & Price

Ready for your server: Undertale has versions for Fabric. Create your world with Fabric and Minecraft 1.21, the combo its latest release is built for.

What is Undertale?

Minecraft Full Undertale map Experience (Part 1-2)
Description by Clouser on Modrinth.

Author: Clouser
Categories: adventure, challenging and combat
Loaders: Fabric
Minecraft versions: 1.21
Latest version: Undertale 0.0.5 (Fabric, May 23, 2025, 96.7 MB)
Mods included: 40 from Modrinth (the pack may bundle more inside)
Downloads: 174,893
Where it installs: Players: required · Server: required
Link: Undertale on Modrinth

Which Minecraft version and loader to play it on

Every world has its own Minecraft version and loader (vanilla, Fabric, Forge or NeoForge); you pick them when you create it.

For Undertale, choose Fabric and Minecraft 1.21: that's what its latest release uses. Here are all the combos available:

Loaders and Minecraft versions you can play Undertale
Loader	Newest	Minecraft versions
Fabric	1.21	1.21

How much RAM Undertale needs

Large (16 GB). Its latest version ships at least 40 mods from Modrinth; on top of that, its file weighs 96.7 MB, a sign it bundles extra mods or resources inside the pack, so we suggest going one size up. Heavy modpacks or lots of players.

Want the full rule of thumb? It's in the modded server guide.

What a Undertale server costs

You only pay while the server is on, and it shuts itself off after 6 minutes with no players. Here's your month based on how many hours you play each week, storage included.

All the details are on the pricing page. Prices in Mexican pesos (MXN).

Monthly cost in MXN for Undertale
Size	5 h/week	10 h/week	20 h/week
Small (4 GB)	$78.75	$117.10	$193.80
Medium (8 GB)	$122.53	$195.33	$340.93
Large (16 GB) · recommended	$203.64	$345.13	$628.09

How to set up your Undertale server

Create your account, top up your balance and create a Large server.
Create the world with Fabric as the loader and Minecraft 1.21 as the version.
In "Mods", add Undertale's mods from the Modrinth catalog (the list is in the dependencies tab of its Modrinth page). The catalog only shows what works with your world, and the panel installs the right version of each mod along with its libraries.
Start the server. The first boot takes a bit longer because it downloads and installs the mods.
Your friends download the .mrpack modpack from the panel in one click and import it in the Modrinth App or Prism Launcher.
Share the server address and you're in: they join through Multiplayer.

First time? The guide to making a Minecraft server takes you step by step.

Frequently asked questions

Which Minecraft version does Undertale need?

Undertale has versions for Fabric: 1.21. The newest is "Undertale 0.0.5" (May 23, 2025). Create your world with Fabric and Minecraft 1.21: that's the combo its latest release is built for.

Can I change the server's Minecraft version later?

Yes, upward: when Undertale ships a newer version, you update and the panel backs up your world first. Going back down isn't possible, because Minecraft can't open worlds saved on a newer version; to play an older one, create another world.

How much RAM does a Undertale server need?

We recommend a Large server with 16 GB. Its latest version ships at least 40 mods from Modrinth; on top of that, its file weighs 96.7 MB, a sign it bundles extra mods or resources inside the pack, so we suggest going one size up. If lots of people play at once or you explore a ton, size up from the panel without losing your world.

Do my friends have to install Undertale to join?

Yes: every player needs Undertale in their Minecraft, on the same versions as the server. The easiest way is to import the modpack in the Modrinth App or Prism Launcher. If you build the server from the panel's catalog, the .mrpack they download has exactly the same mods.

How much does a Undertale server cost?

With a Large server and 10 hours of play a week, about $345.13 MXN a month, storage included. With 5 hours, about $203.64 MXN. You only pay while the server is on; if nobody's playing, it shuts itself off.

Can I play Undertale on an offline-mode (non-premium) server?

Yes. Offline mode is a server setting, not a modpack one: you turn it on in the panel's "Access" tab. Use it with the whitelist on and no operators, because in that mode the server doesn't verify who each player is.