# Experience level
Your experience level in NetHack is a measure of the overall power of your hero and progress of your adventure. You start at level 1, and can level up to 30 at the highest. As you gain experience, you become better at both fighting and magic, but more difficult monsters are generated.
Experience points (XP) are the units that you accumulate to increase your level. Depending on the showexp option, you may see a display of your XP or only see your current experience level.

Contents

1 Effects

1.1 Benefits
1.2 Drawbacks
1.3 Thresholds

2 Gaining levels
3 Losing levels

3.1 Deliberate level drain

4 Experience points required per level

4.1 Total
4.2 Per level

5 Messages
6 Monsters
7 Strategy
8 Variants

8.1 SLASH'EM
8.2 UnNetHack
8.3 FIQHack
8.4 EvilHack

9 References
10 External links

Effects
Gaining an experience level has a number of effects on gameplay:

Benefits
Your maximum hit points and their recovery increase.
Your maximum energy and its recovery increase.
You gain an additional skill slot.
Your chance of hitting in combat increases.
Your chance of successfully learning spells from uncursed spellbooks increases.
At levels divisible by three, your spellcasting success rate increases.
The chance of your spells overcoming monster magic resistance increases.
The spell of magic missile deals more damage.
The spell of protection grants more AC at level powers of 2.
You are more likely to convert an altar.
A spellbook granted as a favor is more likely to be a useful one.
You are more likely to successfully play certain musical instruments, and the range of some of their effects increases.
You are more likely to find a container trap when searching for it.
A Rogue deals more backstab damage.
At specific levels, the range of the turn undead command increases, and the duration of the helplessness it causes decreases.
High-level polyself forms last longer.
Nurses are more likely to raise your maximum hit points.
The average enchantment of generated items determined by rne very slightly increases.
Drawbacks
More difficult monsters are able to be generated, and they can be generated at higher monster levels.
Monster groups are larger.
Protection and other favors from an aligned priest become more expensive.
The summon nasties monster spell can summon more monsters.
A squeaky board can awaken monsters from further away.
Thresholds
Certain roles gain intrinsics at specific levels.
You must at be least level 3 to receive a sacrifice gift.
An elf gains sleep resistance at level 4.
Lawful characters must be at least level 5 to dip for Excalibur.
Wizards must be level 8 to invoke teleportitis at will, while other characters must be level 12.
Monsters become more proactive about fleeing or healing themselves at levels 10 and 14.[1]
You must be level 14 to get permission to begin the Quest from your Quest leader.
A Tourist at level 15 is no longer automatically considered a sucker by shopkeepers.
The turn undead command may pacify or destroy certain classes of undead at specific level thresholds. At level 16, it may also turn demons.
Gaining levels
There are several ways to gain an experience level, ranging from obvious to somewhat obscure:

Experience points (mostly from killing monsters)
Quaffing a blessed or uncursed potion of gain level
Eating a wraith corpse
Chance from incubus or succubus encounter
Chance when polymorphing into your own race
Chance of regaining a lost level when praying successfully at a coaligned altar
Regaining a lost level when quaffing a potion of full healing. Up to half of your lost levels can be regained this way.
Regaining a lost level when quaffing a potion of restore ability. All of your lost levels can be regained this way; all at once if the potion is blessed.
You may never gain more than one experience level at a time; killing a water demon at XP1:0 will only put you on 2:39, not 4:148 as might be expected. (You can, however, gain multiple experience levels in a single turn, as for example when a beginner character manages to destroy many creatures at once with an exploding gas spore.)
If you are already at level 30, experience points will not raise your level. Except for polymorph, effects which instantly increase your level can still increase maximum HP and energy at level 30.

Losing levels
The following effects can decrease your experience level:

Level drain attacks
Monster attacks—vampire bite, wraith touch, or Demogorgon sting
Getting hit by the Staff of Aesculapius or Stormbringer
Casting the drain life spell on yourself.
Chance from foocubus encounter
Chance when receiving a god's anger from incorrect prayer or sacrifice
Chance when polymorphing into your own race
Drain resistance protects against all these except polymorph.  In addition, magic cancellation protects against level drain from monster attacks.
Having a level drained puts you a single experience point below the threshold of the level you just lost.[2] If you gain any experience at all, you will regain a lost level, but only one level can be restored in this way. A blessed potion of restore ability will immediately restore all lost levels to your former maximum, while uncursed potions of restore ability and blessed potions of full healing will restore one level at a time. However, full healing will only restore half of the levels that were lost (rounded up). 
When losing a level, your HP and maximum HP are both decreased by the amount they had increased when you last gained the lost level, to a minimum of one. Energy and maximum energy work similarly, down to a minimum of zero.[3] Being drained below experience level one is deadly, although an amulet of life saving can rescue you, leaving you at level one with no experience.[4]

Deliberate level drain
You may sometimes want to deliberately drain levels for several reasons:

Donation rewards from aligned priests are cheaper at lower levels.  By draining to level 1, you may be able to cheaply buy many points of protection and enough turns of intrinsic clairvoyance to last the rest of the game.
If you have increased your constitution or wisdom since you gained your present levels, you may drain and regain your levels to increase your maximum HP and Pw.
If you have spent skill points enhancing a skill that you no longer find useful, you may drain levels to lose skill points until the skill is un-enhanced, then regain levels and reallocate the skill points to a more useful skill.
Lower-difficulty monsters will be generated when your level is lower.
Be careful that you do not accidentally drain below level 1 or get killed by unexpected combat while you have low HP, no skill points, and a lower to-hit.  You may want to wear an amulet of life saving as insurance.
You will probably want to regain all your lost levels with a blessed potion of restore ability after the purpose of the deliberate level drain is fulfilled.
In versions prior to NetHack 3.6.0, a bug called "drain for gain" existed.  This bug allowed players to gain an arbitrary amount of maximum HP and Pw by repeatedly lowering their stats, draining levels, regaining stats, and regaining levels, since HP and Pw loss during level drain was based on current stats.  Since NetHack 3.6.0, the HP and Pw gain are remembered when gaining a level, and the remembered amount is subtracted when draining, so this exploit no longer works: you can now only gain a finite amount of HP and Pw through drain and regain.

Experience points required per level
Several variants alter the experience requirements to reach each level; these are included in the tables below. (xNetHack and SpliceHack-Rewrite use the FIQHack column.)

Total

Level
NetHack
SLASH'EM
dNetHack
FIQHack
SLEX
EvilHack

1
0
0
0
0
0
0

2
20
40
20
20
20
20

3
40
80
50
40
40
40

4
80
160
100
80
80
80

5
160
320
200
160
160
160

6
320
640
400
320
320
320

7
640
1,280
800
640
640
640

8
1,280
2,560
1,600
1,280
1,280
1,280

9
2,560
5,120
3,200
2,560
2,560
2,560

10
5,120
10,000
6,400
5,120
5,120
5,120

11
10,000
20,000
10,400
10,000
10,000
10,000

12
20,000
40,000
15,600
15,000
20,000
20,000

13
40,000
80,000
22,800
21,000
40,000
40,000

14
80,000
150,000
32,500
28,000
80,000
80,000

15
160,000
250,000
45,200
36,000
130,000
160,000

16
320,000
300,000
61,900
45,000
200,000
320,000

17
640,000
350,000
83,100
55,000
280,000
640,000

18
1,280,000
400,000
109,300
66,000
380,000
960,000

19
2,560,000
450,000
141,000
81,000
500,000
1,280,000

20
5,120,000
500,000
178,700
100,000
650,000
1,600,000

21
10,000,000
550,000
223,000
142,000
850,000
1,920,000

22
20,000,000
600,000
274,500
188,000
1,100,000
2,240,000

23
30,000,000
650,000
333,800
238,000
1,400,000
2,560,000

24
40,000,000
700,000
401,500
292,000
1,800,000
2,880,000

25
50,000,000
750,000
478,200
350,000
2,300,000
3,200,000

26
60,000,000
800,000
563,900
412,000
3,000,000
3,520,000

27
70,000,000
850,000
659,600
478,000
3,800,000
3,840,000

28
80,000,000
900,000
766,300
548,000
4,800,000
4,160,000

29
90,000,000
950,000
885,000
622,000
6,000,000
4,480,000

30
100,000,000
1,000,000
1,000,000
700,000
8,000,000
4,800,000

Per level

Level
NetHack
SLASH'EM
dNetHack
FIQHack
SLEX
EvilHack

1
0
0
0
0
0
0

2
20
40
20
20
20
20

3
20
40
30
20
20
20

4
40
80
50
40
40
40

5
80
160
100
80
80
80

6
160
320
200
160
160
160

7
320
640
400
320
320
320

8
640
1,280
800
640
640
640

9
1,280
2,560
1,600
1,280
1,280
1,280

10
2,560
4,880
3,200
2,560
2,560
2,560

11
4,880
10,000
3,600
4,880
4,880
4,880

12
10,000
20,000
4,000
5,000
10,000
10,000

13
20,000
40,000
5,000
6,000
20,000
20,000

14
40,000
70,000
6,000
7,000
40,000
40,000

15
80,000
100,000
7,000
8,000
50,000
80,000

16
160,000
50,000
9,000
9,000
70,000
160,000

17
320,000
50,000
11,000
10,000
80,000
320,000

18
640,000
50,000
13,000
11,000
100,000
320,000

19
1,280,000
50,000
15,000
15,000
120,000
320,000

20
2,560,000
50,000
17,000
19,000
150,000
320,000

21
4,880,000
50,000
20,000
42,000
200,000
320,000

22
10,000,000
50,000
23,000
46,000
250,000
320,000

23
10,000,000
50,000
26,000
50,000
300,000
320,000

24
10,000,000
50,000
29,000
54,000
400,000
320,000

25
10,000,000
50,000
32,000
58,000
500,000
320,000

26
10,000,000
50,000
36,000
62,000
700,000
320,000

27
10,000,000
50,000
40,000
66,000
800,000
320,000

28
10,000,000
50,000
44,000
70,000
1,000,000
320,000

29
10,000,000
50,000
48,000
74,000
1,200,000
320,000

30
10,000,000
50,000
55,000
78,000
2,000,000
320,000

The following graphs show the amount of XP required for each level in vanilla, SLASH'EM, dNetHack, EvilHack, and FIQHack (xNetHack and SpliceHack-Rewrite use the same graph).

Messages
Welcome to experience level 

<x>.
You gained a level.
Aloha level <x>.
You lost a level as a Tourist.
Sayonara level <x>.
You lost a level as a Samurai.
Farvel level <x>.
You lost a level as a Valkyrie.
Fare thee well level <x>.
You lost a level as a Knight.
Goodbye level <x>.
You lost a level as any other role.
Monsters
Main article: Monster level
Monsters also have experience levels, but they are largely a function of their maximum hit points. When a monster (usually a pet) kills another monster, it gains a few maximum hit points. Unlike the player, monsters do not gain current hit points when their max HP increases. Some monsters can grow up into more mature monsters by gaining experience levels.

Strategy
Every character must reach level 14 at some point to complete their Quest and retrieve the Bell of Opening, required for the Invocation ritual. In general, levels beyond 14 only provide a real power boost for characters who are heavily into spellcasting. Other characters get more HP and to-hit chance, but alchemy, nurse dancing, Luck, and enchanting your weapon can substitute for these boosts. The minor gains from higher levels should be weighed against the more powerful monsters that a high-level character will face.
Most characters can level up to 10 or 11 fairly easily just by killing monsters. However, since the required experience points double with each level, while the points granted by more difficult monsters rise more slowly, you will most likely have to resort to alternative leveling methods to reach level 14. For example, a level 13 character would need to descend to at least dungeon level 23 to fight a Jabberwock, a rare and very dangerous monster. They would then need to kill 82 Jabberwocks just to reach level 14; most other monsters they would encounter grant far less experience.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

You can bypass the Quest level requirement by killing your Quest Leader, but this comes with severe penalties. It's only recommended for speed runners or characters who have locked themselves out of the Quest, not for those who simply don't want to level up.
Variants
SLASH'EM
Getting zapped with the drain life spell or a wand of draining drains an experience level. Using draw blood to make a potion of vampire blood also drains a level, but you are put at the minimum experience for the new level; killing a monster won't get the level back.
In SLASH'EM, a character usually gains enough experience to reach XL 30 naturally without farming. This advantage is slightly balanced by the higher experience requirement at low levels; most early characters will be about one level lower than their vanilla counterparts.

UnNetHack
In UnNetHack, Monks receive the message "Punardarsanaya level <x>" when losing a level.

FIQHack
In FIQHack, the EXP formula was replaced and it is generally much easier to gain new levels after level 10.
Level-draining melee attacks are no longer blocked by MC, each successful attack will drain a full level.
While you are level drained, experience gain is boosted significantly.  Quaffing a blessed potion of full healing will restore all lost levels, not just half.

EvilHack
In EvilHack, it's still an exponential growth curve like vanilla, but the curve ends sooner (level 17 instead of 22), and the experience needed to progress is much less (320,000 per level instead of 10,000,000 per level). The logic being, the player can reasonably/realistically reach the maximum experience level from killing monsters only, without it being too easy to do so.

References

↑ src/muse.c in NetHack 3.6.6, line 399

↑ src/exper.c in NetHack 3.6.1, line 235

↑ src/exper.c in NetHack 3.6.1, line 214

↑ src/exper.c in NetHack 3.6.1, line 205

External links
HP and power starting values, level increases, and regeneration in NetHack 3.4.3

This page is based on a spoiler by Dylan O'Donnell. The original license is:
Redistribution, copying, and editing of these spoilers, with or without modification, are permitted provided that the following conditions are met:

The original contributors to any spoiler must continue to be credited.
Any modifications to the spoiler must be acknowledged and credited.

</x></x></x></x></x></x></x>