Doom metrics
health and damage values, common sizes and dimensions for Doom maps
Below are some core gameplay values and numbers that are useful for level design in Doom / Doom 2.
However, keep in mind this is an action game with aiming and dodging -- so the actual damage and damage per second (DPS) will depend heavily on enemy behavior, available cover, height changes, enemy composition, etc.
For more on what metrics are and why they're useful, see Metrics.
MAP07 "Dead Simple" from Doom 2, by American McGee and Sandy Petersen

World metrics

Units and scale

Doom uses a grid with power-of-two numbers (e.g. 8, 16, 32, 64, 128, 256...) and textures are designed to work in increments of 8, 16, or 32.
Doom's graphics were designed for a 16:10 aspect ratio stretched vertically by 20% with non-square pixels for a 4:3 display. Today, this results in a lot of its art assets to appear vertically "squished". It also distorts any attempt at a coherent real world scale for Doom, which we can guess at: 16 horizontal Doom units = 10 vertical Doom units = 1 foot = 0.6 meters.
Typical map structure
Width in units
Hallway (very narrow), crate, teleport pad
64
Hallway (narrow), big door, wall textures
128
Small room
256-512
Medium room
512-1024
Large room
1024-1536
Average map size from Doom 1, Episode 1
~4000
Maximum map size (recommended, minimal glitches)
32767 (+/- 16384)
Maximum map size (technical, buggy and unstable)
65535 (+/- 32768)
Maximum map size: to calculate distances, Doom uses 16-bit signed integers which have a maximum value of +/- 32767. However, if you actually built a map that stretched from -32767 to +32767 (across 65535 units!) and somehow tricked the engine into running it, then it would still break other distance calculations like a monster's line of sight, because a value of 65535 would overflow past +32767 to become 0. For best results, keep all map geometry within 16384 units of the (0, 0, 0) origin.

Weapon metrics

Doom randomly simulates damage values by rolling virtual dice with each hit. For the shotguns, there's an additional buckshot spread simulation where each pellet must connect with the hitbox for full damage.
The damage per second (DPS) is a rough estimate based on the fire rate multiplied by the average damage per shot.
Weapon
Type
Effective Range
Fire rate per second
Damage per shot
Damage per second (DPS)
Fist
Melee
0-32
2 punches
2-20
22
Berserk Fist
Melee
0-32
2 punches
20-200
220
Chainsaw
Melee
0-33
9 revolutions
2-20
90
Pistol
Hitscan
0-512?
2.5 bullets
5-15
25
Shotgun
Near
0-192?
1 shot (7 pellets)
5-15 * 7 =
35-105
70
Super Shotgun
Close
0-128?
1 shot (20 pellets)
5-15 * 20 =
100-300
150
Chaingun
Hitscan
0-512?
9 bullets
5-15
90
Rocket Launcher
Mid / Long
128-512?
1 rocket (+ splash, 128 unit range)
20-160 +
0-128
150
Plasma Gun
Mid
0-384?
12 cells
5-40
270
BFG 9000
Mid
0-384?
1 shot (+ 40 tracers, 1024 unit range)
100-800 +
49-87
~1200
Most maps begin with players killing low health enemies with the pistol and shotgun. Eventually the player relies more on the chaingun, super shotgun, and rocket launcher, while occasionally switching to the plasma gun for tougher enemies.
The rocket launcher, plasma gun, and BFG are usually less effective at very long range because of the lag built into their projectiles' travel time. At long distances, a monster can move out of the way before getting hit. Doom's autoaiming and randomized monster movement also means it can be tricky to lead shots. You can balance long range encounters toward the player's favor by placing monsters on pillars with no cover, limiting their ability to dodge the player's projectiles.

Monster metrics

Monster sight and hearing

Monsters can look in cardinal (N, E, S, W) and ordinal (NE, SE, SW, NW) directions, essentially in 45 degree increments. They have a 180 degree sight cone based on their initial facing, and can hear combat sounds based on areas bounded by linedefs set to block sound.
If set to "ambush" mode, monsters have a 360 degree sight cone and ignore sounds.

Monster movement

Minimum hallway size is given as (monster width + 2) x (monster height + 2) but in practice, your hallways should usually be much wider since monsters might "step" in larger increments, and monsters block other monsters. Narrow off-angle hallways will force monsters into slower zig-zag movements, because remember, they can only turn and move in 45 degree increments.
Stairs are tricky for monsters. In general, steps with long depths and shallow rises are always more dependable. Step height must always be 24 units or less (or else the monster won't cross) and minimum step depth / maximum slope is proportional to the monster width. For example, for a step that is 24u high, a trooper requires a step that is 33u deep (35 degree rise, 2:3 ratio) while a demon is wider so it requires 51u deep (25 degrees, 1:2 ratio). If you want to see the bounding box calculations yourself, see the PCheckPosition() and PTryMove() functions in p_map.c of the Doom source code.
To simplify building for monsters, we generally recommend:
  • Minimum hallway size: 128 wide x 128 tall, mostly built orthogonally at 90 degree angles to align with the grid with occasional 45 degree angles.
  • Stairway step size: 16 high x 64 deep (15 degree rise, 1:4 ratio) or 8 high x 32 deep.

Monster combat

Monsters will use melee attacks within 64 units of their target, though the Revenant will attempt to use a melee attack within 196 units even if the target is too far. If further than 64 units, then monsters with ranged attacks are more likely to use attack the closer they are to the player, up to a maximum distance of 2048 units. But the Arch-vile has a particularly dangerous ranged attack, so it will only attack within 896 units.
When hit, monsters have a random chance to be stunned in a pain state -- weapons with fast fire rates (chain gun, plasma gun) or multiple projectiles (shotgun, super shotgun) are particularly good at stunlocking monsters and interrupting their attacks.
For much more on monster behavior and debugging, see "Monster behavior" on The Doom Wiki.

Doom 1 monsters

Monster
Health
Pain chance
Min. hallway size (w x h)
Min. step depth (24u high step)
Player
100
--
33 x 58
1
Zombieman (trooper)
20
80%
42 x 58
33
Sergeant (shotgun guy)
30
68%
42 x 58
33
Imp (fireball demon)
60
80%
42 x 58
33
Lost Soul (flying skull)
100
100%
34 x 58
--
Demon / Spectre (fast pig)
150
71%
62 x 58
51
Cacodemon (big flyer)
400
50%
64 x 58
--
Baron of Hell (hunky goat)
1000
17%
50 x 66
41
Spiderdemon (boss)
3000
13%
258 x 102
254?
Cyberdemon (final boss)
4000 (+50% rocket resist)
5%
82 x 112
74?

Doom 2 monsters

Doom 2 includes all the Doom 1 monsters, and added more mid tier monsters designed to survive longer and interact with other monsters.
Monster
Health
Pain chance
Min. hallway size (w x h)
Min. step depth
(24u high step)
Heavy weapon dude (chaingunner)
70
68%
42 x 58
33
Revenant (skeleton with missiles)
300
40%
42 x 58
33
Pain Elemental (big flyer, spawns Lost Souls)
400
50%
64 x 58
--
Arachnotron (baby spiderdemon)
500
50%
130 x 66
124?
Hell Knight (baby cyberdemon)
500
17%
50 x 66
41
Mancubus (big flamethrower monster)
600
31%
98 x 66
90?
Arch-vile (flame zombie, resurrects monsters)
700
3%
42 x 58
33

Item Economy

Ammo pickups

Small
Large
Default ammo with weapon
Dropped by monsters
Bullets
Clip (10)
Pistol, chaingun (20)
Zombieman (5, or 10 on Hard+)
Shells
Shotgun (8), super shotgun (8) (in Doom II)
Rockets
Rocket (1)
Cells
Energy cell (20)
Plasma rifle (40), BFG9000 (40)

Sources