IDKFA

Some Doom cheats give you one ability; IDKFA effectively changes your entire loadout. It is the code for the player who wants to stop worrying about what weapons and ammunition a particular level has provided and start experimenting with the complete arsenal instead. That makes it particularly useful for testing weapons, exploring maps, or simply seeing how a level plays when resource management is removed from the equation.

What the Initials Mean

The ID prefix is a developer signature shared by all of Doom’s cheat codes — a nod to id Software, the studio that created the game. The remaining three letters, KFA, carry a more colorful etymology. According to John Romero, speaking in The Official Doom Survivor’s Strategies & Secrets, KFA stands for “killer fucking arsenal.” Over the years, the player community has generated its own interpretations, the most common being “kick fucking ass” and the more descriptive “keys and full ammo” — the latter being an almost literal description of what the code actually provides.

How It Differs from IDFA

Doom also includes a sibling cheat, IDFA, where FA stands for “full ammo.” The two codes are functionally identical with one meaningful distinction: IDFA omits the keys. A player who needs to restock weapons and ammunition without unlocking doors can use IDFA; a player who wants the complete loadout — weapons, ammo, armor, and all key colors — reaches for IDKFA. The acknowledgment message for IDFA reads “Ammo (no keys) Added,” making the omission explicit. IDFA was not present in versions of Doom prior to 1.666.

Using the Code

To activate IDKFA in PC versions of the game, the player simply types the sequence while playing. There is no need to open a menu or pause the action — the game reads keyboard input in real time during play, including while the automap is open. Once the final letter registers, the confirmation message appears at the top of the screen and the status bar updates to reflect the new inventory state.

One practical caveat concerns keyboard layout. Doom reads raw hardware scan codes rather than localized key mappings, which means the physical key positions matter more than the printed letters on the keycaps. In France, where the AZERTY layout is standard, the key that occupies the position of A on a QWERTY board produces a different scan code. As a result, French players on AZERTY keyboards would type idkfq — the physical equivalent — rather than the canonical spelling.

Cheat codes in Doom are disabled on the “Nightmare!” skill level, with the exception of iddt and idclev. The Doom Classic Unity port and Doom + Doom II are exempt from this restriction, allowing cheat codes to function regardless of the selected skill level.

Behavior in Source Ports and Modern Releases

The cheat has been preserved across decades of ports and re-releases. In the Doom Classic Unity port, some cheat codes — including IDKFA — were made accessible through the settings menu rather than requiring direct keyboard input. Starting with Doom + Doom II’s first update, players gained access to most cheat codes through a dedicated cheat menu built into the game. The Android version of that port additionally supports entering codes via a physical keyboard connected through an OTG cable.

Behavior can vary depending on which source port is in use. Some ports implement the code exactly as the original executables do; others extend or modify it. The Doom Wiki’s source port cheat codes article documents port-specific variations for players who have moved beyond vanilla Doom.

Cultural Footprint

IDKFA’s name recognition has extended well beyond Doom itself. Other games have incorporated references to it, sometimes inverting its function as a joke. Typing iddqd or idkfa in Heretic backfires: the codes either kill the player or remove all of their weapons.

The phrase also inspired IDKFA, a fan-made game by Aleksander Trojanowski released in June 2001. Built on a custom QuickBASIC engine and borrowing Doom’s sprites and textures, it served primarily as Trojanowski’s first attempt at a 3D shooter rather than a direct commentary on the cheat itself. The final release was version 2.1.

Context Within Doom’s Cheat System

Doom ships with a compact but varied set of cheat codes covering god mode (iddqd), no-clipping movement (idspispopd in Doom, idclip in Doom II), power-up toggles (idbehold), level warping (idclev), automap reveals (iddt), and music substitution (idmus). IDKFA occupies the top of the offensive tier — the single code that transforms a depleted player into a fully armed one, ready for any encounter the current level can produce.

For the complete list of Doom cheat codes and their effects, see the Doom cheat codes article on the Doom Wiki.