World Size Check

An oversized world will typically manifest as FoundryVTT having a very slow initial load-in, or failing to load at all.

A good rule of thumb for world sizes is:
Normal: <= 10 MB
Large: 10-20 MB
Huge: 20-40 MB

Typically you’ll start to see trouble around the 30+ MB mark. This is around the fact that FoundryVTT sends the world databases (that comprise that size) to every player on load. This will hurt players/users with slow internet connections the most.

NOTABLE EXCEPTION: If you have things in Compendiums in-world, your world db files can be sized perfectly fine, but the whole “World” size will still be massive, and you won’t see the loading issues. Compendiums are not loaded to all users on World load (thankfully).

How do you check World Sizes on The Forge?
Quite easily! First, don’t try to determine your world size from an export (which you can do here:, that zip will be compressed-size, which isn’t helpful for our purposes.

To find accurate World Size on The Forge:

  1. Navigate to here:
  2. Click “Select Data Files to Delete” (we won’t actually be deleting anything)
  3. Take a look at the “Worlds” tab, as below

(Major caveat, and the importance of the below checks, Compendiums can be large, and WON’T hurt world loading speed, but DO contribute to World Size).

If you have worlds that load strangely, please join us on The Forge Discord ( and ask for help in #forge-help, we’ll be happy to give you a hand!

World Size Troubleshooting
We have often seen issues caused by modules where, due to some bug, the module will jam garbage into one (or more) of the world database files. This can result into worlds that balloon from a nice, safe 5-10 MB up to in excess of 500 MB (I believe we’ve seen a max of 750 MB before).

To find the troublesome module:

  1. Navigate here:
  2. Click “Export World(s)”
  3. Unzip the zip that downloads
  4. Navigate to the unzipped folder
  5. Now navigate into the “data” folder, which contains the db files of the FoundryVTT world
  6. Hunt for a db file that seems excessively large

IMPORTANT NOTE: Fog.db will be large simply by its design (it’s storing the Fog of War exploration for all players). It will lend itself to increased world load-in time, but not negatively affect overall world performance otherwise. You can slim fog.db down by moving Scenes you don’t need into Compendiums, or disabling “Fog of War Exploration” for scenes you don’t need it on.

In the above case, it appears my chat.db is getting pretty large, in order to help my Players and I loading into FoundryVTT, I could clear the chat log (in FoundryVTT on The Forge) to get things working again.

  1. Lets also check the “packs” folder, which is the folder containing in-world Compendiums, these ones won’t count negatively towards world loading. In this case, I only have one Compendium database, ddb-items.db, and it appears empty.

Fixing an enormous chat log (FoundryVTT won’t even load)

  1. Export World
  2. Unzip the export
  3. delete the chat.db file
  4. Use “Summon Import Wizard” here: to re-upload the world

Fixing an enormous actors.db or items.db

  1. Export World
  2. Unzip the export
  3. Use a text editor (like Notepad++) to find the offending section (typically a massive repeat of something, like commas, or 0,0,0,0,0,0,0,0,0,0)
  4. Delete the offending repeating information
  5. Use “Summon Import Wizard” here: to re-upload the world

Hi Mr. Aeristoka, thanks for drawing attention to this!. I noticed the monsters, spells and items in my world in DDB compendium represent more than 10MB. I imported all this using Mr Primates DDB Muncher and I really don’t need ALL the monsters stored in the world I am playing. Will it help to delete my DDB Monster compendium, and then import with Mr Primate’s Muncher ONLY the monsters I am using?

If things are in Compendiums, that’s just fine. Compendiums don’t affect World-loading in the same way the other Databases do.


I exported my game world for inspection and discovered that its data folder is ~28 MB. However, the individual files in the data folder are fairly even in size:

  • actors.db = 1.1 Mb
  • chat.db = 4.3 Mb
  • combat.db = 1 kb
  • fog.db = 4.5 Mb
  • folders.db = 7 kb
  • items.db = 5.7 Mb
  • journal.db = 6.9 Mb
  • macros.db = 16 kb
  • playlists.db = 18 kb
  • scenes.db = 3.6 Mb
  • settings.db = 92 kb
  • tables.db = 1.6 Mb
  • users.db = 6 kb

Does this mean nothing is especially excessive and my “huge” game world just is what it is? Or is there optimization in store?

The first thing I notice, you have TONS of Items & Journals. FoundryVTT itself (no matter where you host) chokes on too many Items/Actors/Journal Entries, so I’d say clean that out a bit for things to work better (you might be ok for the moment).

Could also be there’s some embedded base64 image in the journals/items. That could inflate the size even if the number of entities is small. :thinking:

Thanks! (And @kakaroto too.) I’ll examine closer and see what’s up.

Thanks everyone for this! My game slowed to a crawl (and right after me upgrading my internet connection)! Found out chat.db was around 300M! Running smoothly after applying #aeristoka 's cure above…

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Very happy to hear this! Definitely nice to hear that it’s helping people :smiley:

This is a very helpful post! My “scenes.db” file is nearly 5 MB on its own; however, there is only one scene (with a single 3.36 MB map). What else is stored in that scene.db? My map has walls, journal entries (only two with very small image files attached) and three “sound file” pins. Could that be what is choking the connection for two of my players?

To be fair, those two players are both on Chromebooks.

That’s not too terribly bad for a world size, or a scenes.db really, so it’s likely something else. That said, if it really is one scene in that scenes.db, open it up (with something like NotePad++) and see what it contains in there, that is absurd for one scene.

I’ll shamelessly plug another of my FAQs for things that might slow things down: Trouble with Modules

So I opened it up with Notepad++ and it’s just a ton of code (length 5,060,766 lines: 37). Is there a special formating that will allow me to see the important items?

probably a JSON Pretty Printer (just Google “JSON Pretty Print”), it sounds like your scene might have a base64 encoded Image as the background then, instead of an actual image.

I am actually going through everything and moving all unneeded content into Compendiums. I will let you know if that reduces the size significantly.

How do we know how much of the above world size or .db sizes are in compendiums?

You can check that by going to “Select data content to delete” and modules.

If you want to check how much is in a compendium of a world, export it as shown, and look at the “packs” folder.

Ok thanks.
So as I understand it then, none of the .db content in the data folder is in compendiums? i.e. all that you see there is data that is loaded upon entering the game?

Yes, I do believe so.

That is correct, yes. Data folder for a world is the “world db files”, the “Packs” folder contains compendium db files.

HELLO!! Yesterday during our session the whole game froze making me reboot my PC it has happened twice in a row. So i was sent here for help. I read the above and now i have deleted the chat logs, moved all no needed scenes and journals and items and players into compendiums but I still show massive scene and fog size files… i assume the fog is the fog of war but what happens if I delete it?

world size