IDDQD
Doom's god mode cheat code, granting near-total invulnerability to the player.
IDDQD is a cheat code in Doom and its sequels that activates “Degreelessness Mode,” setting the player’s health to 100% and granting immunity to any damage source inflicting fewer than 1,000 points of damage. Commonly called god mode, the code was created by developer Dave Taylor, whose informal college fraternity Delta-Q-Delta supplied the DQD portion of the name. It is one of the most culturally recognized cheat codes in video game history.
IDDQD is Doom’s answer to the simplest possible cheat request: what if nothing could kill me? Activate it and the usual pressure of health, armor, and incoming fire largely disappears, letting you approach a level with an entirely different set of priorities. The “Degreelessness Mode” it grants is less about giving you another tool to fight with than about temporarily removing one of the game’s central rules.
What the Code Actually Does
According to the Doom Wiki’s cheat code reference, IDDQD grants immunity to any damage source dealing fewer than 1,000 points of damage. The engine function P_DamageMobj in p_inter.c enforces this threshold directly: no standard in-game attack reaches or exceeds that ceiling, making the player functionally invincible under normal conditions. Entering the code a second time toggles degreelessness off, accompanied by the message “Degreelessness Mode Off.”
Two notable exceptions can still end a god-mode run:
- Telefragging — which inflicts 10,000 points of damage, far above the 1,000-point immunity threshold. This is also why MAP30’s Icon of Sin fight is dangerous even in god mode: that map has a hardcoded exception allowing the boss’s spawn cubes to telefrag the player on landing, which kills instantly regardless of invulnerability.
- Damaging floors of sector type 11 — entering or standing on one of these nullifies the invulnerability effect entirely rather than merely dealing damage through it.
Additionally, DeHackEd modifications can create projectiles with damage values exceeding 1,000, circumventing god mode entirely. Projects such as The Sky May Be have demonstrated this effect.
The Name and Its Origin
The “DQD” portion of the code is not arbitrary. Developer Dave Taylor and two fellow hackers invented an informal fraternity they called Delta-Q-Delta during their college years. The Q stands for quit, representing the grade, according to the Doom Wiki, that members should strive to receive in their classes. Membership was contingent on having at least one such mark on one’s transcript. The “ID” prefix is the standard two-letter opener shared by all Doom cheat codes, standing for id Software.
The word “degreelessness” shown in the activation message plays on that same collegiate theme: a fraternity of people deliberately eschewing academic degrees.
Keyboard Layout Considerations
Because Doom’s keyboard interrupt handling reads raw hardware scan codes rather than localized key mappings, the physical keys required to type IDDQD vary on non-QWERTY layouts. On a French AZERTY keyboard, for instance, the Q and A keys are transposed, meaning the equivalent sequence produces different characters. Source ports address this inconsistency in different ways depending on their input handling.
Skill Level Restriction
IDDQD, like most Doom cheat codes, is disabled on the Nightmare! skill level. The exceptions to this restriction are iddt and idclev; IDDQD is not among them. Players using the Doom Classic Unity port or Doom + Doom II are not subject to this restriction.
Behavior in Other Doom-Engine Games
The familiarity of IDDQD made it a natural target for deliberate subversion in companion games built on the Doom engine. In Heretic (Raven Software’s 1994 release, a behavior also carried into its Shadow of the Serpent Riders expansion), typing IDDQD produces the opposite of the intended effect: the player dies immediately, accompanied by the message “trying to cheat, eh? Now you DIE!” This was an intentional easter egg by Raven Software to punish players carrying over muscle memory from Doom.
Source Port Differences
The precise behavior of IDDQD has diverged slightly across source ports, particularly regarding sector type 11. As discussed in historical wiki records, some ports such as PrBoom handle the type-11 floor interaction differently from vanilla Doom and ZDoom. In vanilla behavior, the type-11 sector disables god mode rather than simply overcoming it; port implementations vary on this edge case.
Cultural Footprint
IDDQD became one of the most recognizable strings of characters in 1990s gaming, functioning as shorthand for invincibility well beyond the game itself. Its eight-character sequence appeared on merchandise, in forum handles, and in mainstream press coverage of Doom throughout the game’s rise to cultural prominence. Wikipedia redirects the term directly to the Doom article, reflecting how completely the code became identified with the game rather than standing as a separate reference.
For a complete listing of all Doom engine cheat codes and their effects, see the Doom cheat codes reference on the Doom Wiki.
Frequently asked questions
What does IDDQD do in Doom?
IDDQD activates Degreelessness Mode, setting the player’s health to 100% and granting immunity to any attack or hazard dealing fewer than 1,000 points of damage. Typing it again toggles the effect off.
What does IDDQD stand for or mean?
The “ID” prefix is shared by all Doom cheat codes and stands for id Software. The “DQD” portion references Delta-Q-Delta, an informal college fraternity invented by developer Dave Taylor and two fellow hackers. The Q stood for quit, the grade members should strive to receive.
Can anything kill you while IDDQD is active?
Yes. Two scenarios can still end a god-mode run: a telefrag, which inflicts 10,000 damage — far above the 1,000-point immunity ceiling, and the reason MAP30’s spawn cubes can kill an invulnerable player, since that map has a hardcoded exception letting monsters telefrag on landing — and sector type 11 damaging floors, which nullify the invulnerability effect outright. DeHackEd modifications that create projectiles exceeding 1,000 damage can also bypass god mode.
Does IDDQD work in Heretic?
No. In Heretic — starting with the original 1994 release, and carried into the Shadow of the Serpent Riders expansion — typing IDDQD causes instant death and displays the message “trying to cheat, eh? Now you DIE!” — a deliberate easter egg by Raven Software.
Does IDDQD work on Nightmare! difficulty?
No. IDDQD is disabled on the Nightmare! skill level. This restriction does not apply in the Doom Classic Unity port or Doom + Doom II.
Why does IDDQD behave differently across source ports?
Source ports differ in how they handle edge cases such as the sector type 11 interaction. In vanilla Doom, a type-11 floor disables god mode; some ports such as PrBoom have handled this differently. Input handling on non-QWERTY keyboards also varies, since the original game reads raw hardware scan codes.