Doom WAD is the default format of package files for the video game Doom and its sequel Doom II: Hell on Earth, that contain sprites, levels, and game data. WAD stands for Where's All the Data?[1] Immediately after its release in 1993, Doom attracted a sizeable following of players who created their own mods for WAD files—packages containing new levels or graphics—and played a vital part in spawning the mod-making culture which is now commonplace for first-person shooter games. Thousands of WADs have been created for Doom, ranging from single custom levels to full original games; most of these can be freely downloaded over the Internet. Several WADs have also been released commercially, and for some people the WAD-making hobby became a gateway to a professional career as a level designer.

There are two types of WADs: IWADs (internal WADs) and PWADs (patch WADs). IWADs contain the data necessary to load the game, while PWADs contain additional data, such as new character sprites, as necessary for custom levels.

History of WADs

Development of Doom

When developing Doom, id Software was aware that many players had tried to create custom levels and other modifications for their previous game, Wolfenstein 3D. However, the procedures involved in creating and loading modifications for that game were cumbersome.

John Carmack, lead programmer at id Software, designed the Doom internals from the ground up to allow players to extend the game. For that reason, game data such as levels, graphics, sound effects, and music are stored separately from the game engine, in "WAD" files, allowing for third parties to make new games without making any modifications to the engine. Tom Hall is responsible for coming up with the name WAD.[2]

The idea of making Doom easily modifiable was primarily backed by Carmack, a well-known supporter of copyleft and the hacker ideal of people sharing and building upon each other's work, and by John Romero, who had hacked games in his youth and wanted to allow other gamers to do the same. However, some, including Jay Wilbur and Kevin Cloud, objected due to legal concerns and the belief that it would not be of any benefit to the company's business.

Utilities and WADs

Immediately after the initial shareware release of Doom on December 10, 1993, players began working on various tools to modify the game. On January 26, 1994, Brendon Wyber released the first public domain version of the Doom Editing Utility (DEU) program on the Internet, a program created by Doom fans which made it possible to create entirely new levels. DEU continued development until May 21 of the same year. It was made possible by Matt Fell's release of the Unofficial Doom specifications. Shortly thereafter, Doom players became involved with further enhancing DEU. Raphaël Quinet spearheaded the program development efforts and overall project release, while Steve Bareman lead the documentation effort and creation of the DEU Tutorial. More than 30 other people also helped with the effort and their names appear in the README file included with the program distribution. Yadex, a fork of DEU 5.21 for Unix systems running the X Window System, was later released under the GNU/GPL license.[3] Carmack additionally released the source code for the utilities used to create the game, but these were programmed in Objective-C, for NeXT workstations, and were therefore not directly usable the mass userbase of IBM PC compatible.

Jeff Bird is credited with creating the first custom WAD for Doom, called Origwad, on March 7, 1994.[4] Soon, countless players were creating custom WADs and sharing them over AOL, the CompuServe forums, and other Internet-based channels. Many of the WADs were made in the style of the base game, others were based on existing TV series, movies, or original themes. Some of the id Software staff have revealed that they were impressed by some of the WADs. John Carmack later said the following about a Star Wars-themed modification:

I still remember the first time I saw the original Star Wars DOOM mod. Seeing how someone had put the Death Star into our game felt so amazingly cool. I was so proud of what had been made possible, and I was completely sure that making games that could serve as a canvas for other people to work on was a valid direction.

Another early modification is Aliens TC (Total Conversion), based on the movie Aliens.

Even though WADs modified Doom by replacing graphics and audio, the amount of customization was somewhat limited; much of the game's behavior, including the timing and strength of weapons and enemies, was hard-coded in the Doom executable file and impossible to alter in WADs. DeHackEd, a Doom editing program created by Greg Lewis, addressed this by letting users modify parameters inside of the Doom executable itself, allowing for a greater degree of customization.

Commercial WADs

Around 1994 and 1995, WADs were distributed primarily through BBSs and via CD collections found in computer shops or bundled together with instruction guides for level creation, while in later years Internet FTP servers became the primary method for obtaining these works. Although the Doom software license required that no profit be made from custom WADs, and Shawn Green objected to people selling their WADs for money,[6] but some WAD sets and shovelware bundles were nonetheless obtainable for a price at certain outlets.

During this time, id Software was working on their next game, Quake, using new technology, but started projects picking up the most talented WAD makers from the Doom community to create official expansions and to compete with the unauthorized collection CDs. The team produced the 21 Master Levels, which, on December 26, 1995, were released on a CD along with Maximum Doom, a collection of 1,830 WADs that had been downloaded from the Internet. In 1996, Final Doom, a package of two 32-level megawads created by TeamTNT, was released as an official id Software product.

Various first-person shooter games released at the time use the Doom engine under a commercial license from id Software, as such essentially being custom WADs packaged with the Doom engine, such as Hacx: Twitch 'n Kill (1997).

In addition to the many people who contributed to commercially released WADs, various authors became involved with the development of other games:

Source port era

Main article: Doom source ports

Around 1997, interest in Doom WADs began to decline, as attention was drawn to newer games with more advanced technology and more customizable design, including id Software's own Quake and Quake II.

On December 23, 1997, id Software released the source code to the Doom engine, initially under a restrictive license. On October 3, 1999, it was released again under the terms of the GNU GPL-2.0-or-later. With the source code available, it became possible for programmers to modify any aspect of the game, remove technical limitations and bugs, and add entirely new features.

These engine modifications, or Doom source ports, have since become the target for much of the WAD editing activity, and with the decline of MS-DOS, using a source port became the only feasible way to play Doom for most people. Several source ports are in active development, and Doom retains a strong following of WAD creators.

Types of WADs


The most common type of WAD consists of a single level, usually retaining the theme of the original game, but possibly including new music and some modified graphics to define a more distinctive setting or mood. Both single-player and deathmatch multiplayer levels are common.

WADs may have a level pack in the form of an episode, replacing nine levels, and sometimes in the form of a megawad, which replaces 15 or more levels in the game (27 in Doom, 32 in Doom II, 36 in The Ultimate Doom).

Total conversions

A WAD that gives the game an overhaul to incorporate an entirely different game setting, character set, and story, instead of simply providing new levels or graphic changes, is called a total conversion. The phrase was coined by Justin Fisher, as part of the title of Aliens TC, or Aliens Total Conversion.[7] Add-ons that provide extensive changes to a similar degree but retain distinctive parts or characteristics of the original games, such as characters or weapons, are often by extension called partial conversions.

List of WADs

The following is a select listing of popular and historically significant WADs.


Total conversions


Screenshot from Freedoom
Screenshot from Freedoom


Level 2 (version 0.6.4)
Original author(s)Freedoom project
Initial release16 April 2003; 18 years ago (2003-04-16)
Stable release
0.12.1 / 22 October 2019; 17 months ago (2019-10-22)
PlatformLinux, Microsoft Windows, macOS, MS-DOS, Android, iOS[35]
TypeSingle-player, multiplayer first-person shooter
License3-clause BSD (requires a Doom engine source port under the GNU GPL-2.0-or-later to play)

Freedoom is a project aiming to create a free replacement (modified BSD License) for the set of graphics, music, sound effects, and levels (and miscellaneous other resources) used by Doom.[36][37] Since the Doom engine is free software, it can be distributed along with the new resources, in effect providing a full game that is free and with full third party WAD.

The project distributes three IWAD files: the two single-player campaigns named Freedoom: Phase 1 and Freedoom: Phase 2, and FreeDM, which contains a collection of deathmatch levels.[38] Freedoom does not require any source port to run, and can run on any limit-removing source port of Doom.

A similar project, Blasphemer, aims to create a complete free version of Heretic, but is less fully developed than Freedoom.[39]


Many level editors are available for Doom. The original Doom Editing Utility (DEU) was ported to a number of operating systems, but lost significance over time; many modern Doom editors still have their roots in DEU and its editing paradigm, including DETH, DeePsea, Linux Doom Editor, and Yadex. Other level editors include WadAuthor, Doom Builder (released in January 2003), and Doom Builder 2 (released in May 2009 as the successor to Doom Builder). Some Doom level editors, such as Doom Builder and Doom Builder 2, feature a 3D editing mode. As of now, these two have been discontinued, but a newer fork has been released and is regularly updated, known as GZDoom Builder.[citation needed]

Many specialized Doom editors are used to modify graphics and audio lumps, such asXWE, SLADE, Wintex, and SLumpEd. The DeHackEd executable patching utility modifies monsters, items, and weapon behavior. In ZDoom, users can create new monsters, weapons, and items through a scripting language called DECORATE, made to address many of the shortcomings of DeHackEd, such as not being able to add new objects, and not being able to deviate far from the behavior of the original weapons and monsters.

WAD2 and WAD3

In Quake, WAD files were replaced with PAK files. WAD files still remain in Quake files, though their use is limited to textures. Since WAD2 and WAD3 use a slightly larger directory structure, they are incompatible with Doom.


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Further reading