This help page explains the format of Form IDs for objects and characters from add-ons to Fallout games based on Bethesda Game Studios engine systems.

Please read this page if you have trouble getting the Form IDs to work or if you are wondering why the numbers start with "xx".

What is a Form ID?

A Form ID is a 32-bit hexadecimally expressed index number. Every form object (or "Base" object) and world reference object in the game is assigned a unique Form ID. It is a system first implemented in the Elder Scrolls IV: Oblivion version of Bethesda's in-house adaptation of the Gamebryo engine so that everything, even in subsequent modules (ESM and ESP files) after the main one, can be uniquely identified by the game engine, not relying on potentially duplicable word-based Editor IDs or Game IDs.

Form IDs are called "base id" if they denote the prototype of an object, and "reference id" or short "ref id" for a specific copy of an object in the game world.

Why do Form IDs from DLC packs start with "xx"?

Form IDs from add-ons start with "xx" because their first two numbers vary from player to player, depending on which mods and DLC packs are installed on his/her system.

This is because the load order of modules (ESMs and ESPs) affects those numbers. The first two digits of a Form ID correspond to its load order. The only "fixed" IDs are those from "base" Fallout 3, Fallout: New Vegas and Fallout 4 games (which always start with "00" because it is always loaded first) and those for objects which are/have been created during gameplay such as spawned characters or items (those IDs always start with "FF").


If you have both Operation: Anchorage and The Pitt installed, IDs for characters, objects etc. from Operation: Anchorage will start with "01" (e.g. 010018d2) and IDs for objects from The Pitt will start with "02" (e.g. 02000f20). If you have only The Pitt installed, IDs for its objects will start with "01". If you have mods installed which are loaded before the DLC packs, their numbers will be different entirely (higher).

How do I find out what the first two numbers are for me?

The easiest way is to find a character from a certain DLC, call up the console and click on him/her. His/her ref ID will be displayed at the top of the screen and the first two numbers are the ones all objects, characters etc. from that DLC will have. If you come across a character whose Ref ID starts with "FF" or "00", try a different one. Sometimes, you may end up clicking on a visual effect object (like dust or light beams) that are in the way (oftentimes displayed with no Game ID). To thumb through all objects under the point where you clicked, use the mouse wheel until you find what you're looking for.

Another easy way to find out the ID is to download the Fallout Mod Manager. The program will show the two ID numbers for each DLC/mod.

Fallout 3

You can also calculate the number if you have no mods installed. In general, the add-on load order is:

  1. Operation: Anchorage
  2. The Pitt
  3. Broken Steel
  4. Point Lookout
  5. Mothership Zeta

Go over this list from top to bottom; the first add-on you have will have the numbers 01, the second you have will have 02 etc.

Please note that certain language versions of Point Lookout have a different modified date, causing the load order to be different. In this case, the order is:

  1. Point Lookout
  2. Operation: Anchorage
  3. The Pitt
  4. Broken Steel
  5. Mothership Zeta

Fallout: New Vegas

  1. Dead Money
  2. Honest Hearts
  3. Old World Blues
  4. Lonesome Road
  5. Gun Runners' Arsenal
  6. Tribal Pack
  7. Mercenary Pack
  8. Classic Pack
  9. Caravan Pack

Fallout 4

  1. Automatron
  2. Wasteland Workshop
  3. Far Harbor
  4. Contraptions Workshop
  5. Vault-Tec Workshop
  6. Nuka-World

Creation Club

Each Creation Club mod has its own load order number. The mod starting with the lowest ASCII code name will be loaded first. The form ID of each separate entity is constructed starting with fe0, fourth/fifth position range from 00-09, 0a-0f, then 10-19, 1a-1f and so on. The last three characters are as seen in the Creation Kit.

Example: the BFG 9000 has formid/baseid: fe0xx800

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