Experience points
In NetHack, experience points or XP measure the character's progress toward gaining experience levels. A character gains an experience level when they accumulate sufficient experience points. XP are shown in the status line when the showexp option is on (default: off).
Gaining experience points
Experience points can be gained by:
- Killing monsters.
- Eating tripe, yielding 1 XP, provided hero is not an orc and is not in a polyform that enjoys tripe.[1]
- Consulting the Oracle, for the first major consultation and the first minor consultation.
- Quaffing from a sink, which can give 1 XP (5% chance).[2]
- Untrapping a squeaky board for 1 XP.[3]
- The first novel you read gives 20 XP.[4]
You can also gain an entire experience level, lose an entire experience level, and restore lost experience levels, with commensurate gains and loses in experience points.
Experience points from killing monsters
The number of experience points obtained by killing a monster of level ML is computed as follows:[5]
- Start with 1 + (ML) * (ML).
- Add a bonus for low armor class: +5 for AC 2, +6 for AC 1, +7 for AC 0, and +(14-2*AC) for negative AC.
- Add 3 if the monster's speed is between 13 and 18, and 5 if the monster's speed is at least 19.
- For each attack that the monster has, add a bonus based on attack type:
- +10 for spellcasting attack type,
- +5 for weapon attack type,
- +3 for all other attack types, except for
- +0 (nothing) for passive, claw, bite, kick and headbutt attack types.
- For each attack that the monster has, add a bonus based on damage type:
- +2*ML for magic missile, fire, cold, sleep, disintegration, shock, acid, or strength-draining poison;
- +50 for drain life, stoning, or sliming;
- +ML for any damage type not ordinary physical and not listed in the two lines above;
- +ML for an attack with maximum damage of at least 24;
- +1000 for a sea monster with a drowning attack, if you do not have magical breathing.
- Add 7*ML if the monster is M2_NASTY.
- Add 50 if ML is at least 9.
Next, mail daemons are a special case; they are only worth 1 experience point, overriding all the above.
If this monster has been cloned or revived, the total experience is reduced (but not below 1 XP).
| Kill count (including current) | Reduced XP |
|---|---|
| 1 .. 20 | full xp |
| 21 .. 40 | xp/2 |
| 41 .. 80 | xp/4 |
| 81 .. 120 | xp/8 |
| 121 .. 180 | xp/16 |
| 181 .. 240 | xp/32 |
| 241 .. 255+ | xp/64 |
The result is the number of experience points you earn for killing the monster.
This calculation takes into account all attacks listed in the monster's definition from the source code, including attacks that are not implemented (such as the green slime's passive sliming attack). The armor class and speed used in this calculation are the base values; they do not take into account the armor that the monster might have worn, or the extra speed that the monster might have had from a wand of speed monster, a monster spell, etc. On the other hand, the monster level used here is the monster's actual level at the time it was killed, not the base level or the level at which it was created.
