A player’s health starts at a full 100 percent (or hit points). It may increase even beyond that from the effects of various powerups to as high as 200 percent (199 in versions prior to 1.2). It is decreased by environmental hazards (damaging floors, exploding barrels, and crushing ceilings), and successful enemy attacks. If a player's health ever drops to zero, that player dies.

The player's current health is shown on the status bar, both numerically, as a percentage of the character's full normal health, and graphically, by the condition of the character's face.

If a player wearing armor is attacked, the armor will absorb some of the damage (one third or one half, depending on the type of armor) and thus lessen the decrease in health. Hypothetically, a player with maximized 200 percent health and megaarmor can withstand a total of 400 hit points damage, but in actual play this value is reduced by roundoff effects.

If a level ends while the player is dead, play proceeds to the next level, but with the player's status reset to that of a newly launched game (100 percent health, no armor, the pistol and 50 bullets).

Monster health[edit]

Thing Health
Zombieman 20
Shotgun guy 30
Heavy weapon dude 70
Imp 60
Demon 150
Spectre 150
Lost soul 100
Cacodemon 400
Hell knight 500
Baron of Hell 1000
Arachnotron 500
Pain elemental 400
Revenant 300
Mancubus 600
Arch-vile 700
Spiderdemon 3000
Cyberdemon 4000
Wolfenstein SS 50

Additionally, an exploding barrel has a health of 20, Romero's head has 250 and Commander Keen has 100.