Minecraft Server Seeds: Set, Find and Reset a World Seed

How a Minecraft seed works

A seed is the starting number for the world generator. On the same Minecraft version, the same seed produces the same terrain and biomes. In Java Edition a seed can be a number or a word or phrase, and negative numbers work. Text is converted to a 32-bit number with Java's hashCode(), which limits text seeds to about 4.29 billion different worlds. Seeds made only of digits can use the full 64-bit range.

• Version matters. Whenever Mojang changes world generation, the same seed produces different terrain. A seed from a 2021 video may not look the same on 26.3, which also added the Dappled Forest biome and Abandoned Camps.
• Java and Bedrock differ. Bedrock supports 64-bit seeds as well, and the Minecraft Wiki says terrain and biomes can match between editions for some seeds, but structures, caves and features differ. Do not expect a Java seed to give the identical world on Bedrock.
• The seed does not include your builds. It only decides the generated world. Anything players changed is stored in the world files.

Set a seed for a new world on ChicagoServers

The seed has to be in place before the server creates the world. For a brand-new server, do it before the first start. For a server that has already generated a world, use the next section instead.

1. Stop the server

   Open your server at panel.chicagoservers.co and click Stop if it is running.

2. Open server.properties

   Go to the Configs tab and pick Server properties. If the file does not exist yet, start the server once, stop it, then come back. Servers create the file on the first start.

3. Enter the seed

   Put your seed after level-seed=. Leave it blank for a random seed. Do not add quotes or spaces unless they are part of a text seed.

   Copy

   level-seed=my-seed-text

4. Save and start

   Click Save, then Start or Restart. Watch the Console tab until the server finishes preparing the spawn area.

5. Check it

   Run seed on the Console tab. It prints the seed the world is using, which should match what you entered (a text seed is shown as its number).

Find the seed of a world that already exists

• From the panel: type seed on the Console tab. The slash is optional there.
• In game: run /seed. On a multiplayer server only operators and players with command access can use it. To give yourself access, run op YourName on the Console tab, and see the whitelist and operator guide for permission levels.
• In your own singleplayer world: /seed works even with cheats off.
• Bedrock: the seed is shown on the world's Edit screen, and operators can run /seed.

Why changing level-seed does not re-roll a world

level-seed is only used when the server creates a world. On an existing world the old terrain is already saved, so nothing about it changes. If you edit the seed anyway, any chunks that have never been generated, such as unexplored land, can use the new seed while the explored area keeps the old one. The result is sharp seams where the two meet, so do not use this to get a new map.

Switch to a new seed without losing the old world

The safest way to start over is to give the server a new world name and leave the old folder where it is. The server loads whichever world level-name points at, and generates a new one if that folder does not exist.

1. Back up

   Open the Backups tab, choose World and settings and click Back up now. Star the backup so it is not replaced.

2. Stop the server

   Click Stop. Changing world files while the server is running can corrupt a save.

3. Edit server.properties

   On the Configs tab, open Server properties. Set level-name to a name that does not exist yet and set level-seed to the seed you want, or leave it blank for random.

   Copy

   level-name=world2
   level-seed=my-new-seed

4. Save and start

   Click Save, then Start. The server generates the new world in a new folder. Your old world is still in the Files tab.

5. Go back any time

   Set level-name back to the old name (world by default) and restart to load the old world again. Its level-seed value does not matter because the world already exists.

Players' inventories, advancements and statistics are stored inside each world, so they start fresh in the new world. Tell your community before you switch.

Delete the old world instead

If you do not need the old world, you can delete it and let the server regenerate it under the same name. This cannot be undone, so make a backup first and keep it.

• Stop the server, then open the Files tab.
• Delete the folder named by level-name, which is world by default.
• On servers up to 1.21.11 running Paper, Spigot or Purpur, the Nether and End are separate folders next to it (world_nether and world_the_end). Delete those too, or the old dimensions come back. On 26.1 and later, host documentation reports the dimensions are stored inside the world folder, under dimensions, so deleting the world folder removes them. Look in the Files tab to see which layout yours uses.
• Set level-seed as you want it on the Configs tab, save, and start the server.

Pre-generate the new world

A new world generates terrain as players explore, which is what makes the first hours of a fresh seed laggy. A pre-generation plugin such as Chunky builds the chunks ahead of time. On a plugin server, install it in plugins, then run these commands on the Console tab:

chunky radius 5000
chunky start
chunky progress

Pre-generation writes a lot to disk and keeps the server busy until it finishes, so run it before players arrive. The Nether is eight times smaller than the Overworld, so a 5,000-block Overworld radius needs only about 625 blocks in the Nether. Use tab completion for chunky world, because world names changed in 26.1.

Troubleshooting seeds and new worlds

Setting up a fresh world on a new server? See server.properties explained for the other settings, how much RAM you need, and Minecraft server hosting for what is included.

Frequently asked questions