Form ID

The FormID (or Form ID) of an object is the unique numerical identifier for that object, in hexadecimal.

Overview
This is the short version used by the engine while the game is running. This identifier is assigned by the engine to every object in games using the Gamebryo engine (Fallout 3 and Fallout: New Vegas) or Creation Engine (Fallout 4 and Fallout 76). This includes items, NPCs, quests or parts of the world. Form IDs on Reference objects are referred to as Reference IDs (usually shortened to Ref IDs).

For example, all bottle caps in the game have exactly the same Form ID. This ID is used in scripts or console with commands that create new instances of object, like or.

The Form ID can be obtained with the G.E.C.K., Creation Kit, or xEdit. To do so in the G.E.C.K or Creation Kit, the .esm file containing the object (for base Fallout 3:, for Fallout: New Vegas:  , and for Fallout 4:  ) must be opened in the editor and the appropriate category is selected. In the G.E.C.K and Creation Kit, expanding the "Form ID" column (between "Editor ID" and "Count") will reveal the Form ID.

Unmodified Fallout 3 and Fallout: New Vegas do not provide functionality for easy Form ID search through the console, it is possible, however, to find out the Form ID of objects in Fallout 4 by using the Mod:Console commands (Fallout 4) console command.

Reference ID
The Reference ID is the unique ID of an individual object in the game space. For example, all the bottle caps created from the same base object Form ID will have different reference IDs. This ID is used to manipulate existing objects with commands like, , or , for example.

Any item that is not created by pre-defined game module data (either original or from mods) will have a reference ID starting with FF to indicate that this item belongs to this particular save game. It is for dynamically generated items, like loot from containers, random encounters or trader's wares.

Load order
The load order of modules (ESMs and ESPs) will affect the ID number of modules. The first two digits of an ID number corresponds to its load order (in hexadecimal, like the rest of the number). One must use a utility like FO3Edit to ascertain the load order of a module. The load order ID of the top-level master module (such as Fallout3.esm, FalloutNV.esm, or Fallout4.esm) is always 00, as it will always be the very first module to load. The ID number series in the FF (decimal equivalent: 255) range is reserved by the game engine for objects dynamically created and saved in the game's save file (such as PlaceAtMe'd object, projectiles, dropped inventory, or list-spawned actors).

According to the layout of this system, the maximum number of additional modules that can be loaded by the game is 254 (256 load order ranges, - 1 for the dynamic FF range, - 1 for the always-mandatory top-level master ESM). Each add-on, official or otherwise requires a single module space.

What is a Form ID?
The FormID (or Form ID) of an object is the unique numerical identifier for that object, in hexadecimal. This is the short version used by the engine while the game is running. This identifier is assigned by the engine to every object in games using the Gamebryo engine (Fallout 3 and Fallout: New Vegas) or Creation Engine (Fallout 4 and Fallout 76). This includes items, NPCs, quests or parts of the world, like a sign on a wall or the wall itself.

Every form 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, ESP and ESL 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. Game Setting and Default Object forms, however, do rely on the Editor ID as the unique identifier instead of the Form ID.

Prior to Fallout 4, "Base ID" was used as the nomenclature for the prototype object's Form ID and "Ref ID" for a placed object's Form ID.

Why do Form IDs from DLCs 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 their 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").

Example
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 them. The 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 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.

You can also calculate the number if you have no mods installed. In general, the add-on load order is:
 * Fallout 3
 * 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, the second you have will have   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

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 "FE" for the first two characters, 000-FFF (depending on load order) for the next three, and the last three characters are as seen in the Resource:GECK (program) (Fallout 3, Fallout: New Vegas), Creation Kit (Fallout 4), and xEdit (Fallout 3, Fallout: New Vegas, Fallout 4).
 * Creation Club

Example: the BFG 9000 has a formid of ""