There are plenty of random dungeon generator programs, but several editions of D&D present pen-and-paper friendly processes for manually creating random dungeons. Using a a few dice and some graph paper, you can construct a full dungeon with little manual intervention. While 3.5 and 5e both include rules for this, 4th editions rules were, in my opinion, the best for generating the actual structure of a dungeon. However, the mechanics presented in 4e lack details and versatility presented in the random dungeon and random encounters tables in the 3.5 DMG. By combining the two, we can create a useful, elegant, versatile dungeon generator.

This system could be used in any system with a little adaptation. The dungeons could just as easily be a space hulk, the interior of some huge starship, the alleys of a crowded city, or the corridors of a mad scientist’s laboratory. All you really need to change is the room descriptions so that they fit your desired setting and feel.

Limiting the Dungeon

Depending on your ruleset, you may want to limit the size of your dungeon. It’s pretty common for randomly generated dungeons to run the course of a full character level. For 4th edition, this means 10 encounters. For 3.5, this means about 13 encounters plus change. For pathfinder, this means 13, 20, or 40 encounters depending on the game speed. Once you hit this point, stop generating new parts of the dungeon, and move on to step 3.

Step 1 – Entrance

For some reason, most random dungeon generators skip over the entrance, leaving the crucial question “how do we get in?”. The 4e DMG provides two pre-made entrance tiles complete with a staircase leading down into the dungeon, a few decorative touches, and a few doors and corridors to branch off into your new dungeon. Alternatively, you can use a random corridor or chamber from the tables below.

Step 2 – Generate

Start by attaching corridors to each of the exits from your entrance chamber. The heart of the generator is the Corridors table and the Chambers table.

If any of the tables requires you to generate another item (door, corridor, etc.), it will be marked in bold. Corridors are 1 square wide by default.


If you generate a corridor which runs into another corridor, end the new corridor by connecting it to the intersecting corridor. If the corrdiror hits a chamber, either add a new exit to the chamber, or move one of the unused exits to accomodate the corridor.

1Straight 4 squares. Continues with another corridor.
2Straight 8 squares. Continues with another corridor.
3-5Ends in door. Continues with another corridor on the other side.
6Straight 4 squares, door on right. Continues with another corridor.
7Straight 4 squares, door on left. Continues with another corridor.
8Straight 4 squares, side corridor on right. Continues with another corridor.
9Straight 4 squares, side corridor on left. Continues with another corridor.
10Three-way intersection (“T”). Roll 1d3 to determine which direction to attach to. Continues with another corridor on each branch.
11Four-way intersection. Continues with another corridor on each branch.
1290-degree turn left. Continues with another corridor.
1390-degree turn right. Continues with another corridor.
14-15Ends in chamber (no door).
16Ends in stairs.
17Straight 4 squares, stairs on right. Continues with another corridor.
18Straight 4 squares, stairs on left. Continues with another corridor.
19Dead End.
20Random Encounter


d100Type (DC to break)
01-08Wooden, simple, unlocked
09Wooden, simple, unlocked and trapped
10-23Wooden, simple, stuck (13)
24Wooden, simple, stuck (13) and trapped
25-29Wooden, simple, locked (15)
30Wooden, simple, locked (15) and trapped
31-35Wooden, good, unlocked
36Wooden, good, unlocked and trapped
37-44Wooden, good, stuck (18)
45Wooden, good, stuck (18) and trapped
46-49Wooden, good, locked (18)
50Wooden, good, locked (18) and trapped
51-55Wooden, strong, unlocked
56Wooden, strong, unlocked and trapped
57-64Wooden, strong, stuck (23)
65Wooden, strong, stuck (23) and trapped
66-69Wooden, strong, locked (25)
70Wooden, strong, locked (25) and trapped
71Stone, unlocked
72Stone, unlocked and trapped
73-75Stone, stuck (28)
76Stone, stuck (28) and trapped
77-79Stone, locked (28)
80Stone, locked (28) and trapped
81Iron, unlocked
82Iron, unlocked and trapped
83-85Iron, stuck (28)
86Iron, stuck (28) and trapped
87-89Iron, locked (28)
90Iron, locked (28) and trapped
91-93Door slides to one side rather than opening normally. Reroll type (ignoring rolls of 91+). Add +1 to break DC.
94-96Door slides down rather than opening normally. Reroll type (ignoring rolls of 91+). Add +1 to break DC.
97-99Door slides up rather than opening normally. Reroll type (ignoring rolls of 91+). Add +2 to break DC.
100Door magically reinforced. Reroll type (ignoring rolls of 91+). Break DC is 30 for wooden and 40 for stone or iron doors.


1-2Square, 8 x 8 squares
3-4Square, 10 x 10 squares
5-6Rectangle, 6 x 8 squares
7-8Rectangle, 8 x 10 squares
9-10Rectangle, 10 x 16 squares
11-12Octagon, 8 x 8 squares
13-14Octagon, 8 x 12 squares
15-16Octagon, 12 x 12 squares
17-18Irregular, roughly 8 x 10 squares
19-20Irregular, roughly 10 x 16 squares
19Stairs Only
20One exit plus stairs
For each exit other than stairs, roll 1d20: 1-10, exit is a door 11-20, exit is a corridor
d100Chamber Contents
01-18Monster only
19-44Monster and features
45Monster and hidden treasure
46Monster and trap
47Monster, features, and hidden treasure
48Monster, features, and trap
49Monster, hidden treasure, and trap
50Monster, features, hidden treasure, and trap
51-76Features only
77Features and hidden treasure
78Features and trap
79Features, hidden treasure, and trap
80Hidden treasure only
81Hidden treasure and trap
82Trap only
10Chamber Features
1-41d4 minor features and furnishings
4-81d4 major features and furnishings
9-101d4 minor features and furnishings and 1d4 major features and furnishings
d100Minor FeatureMajor Feature
04Bale (straw)Arrow slit (wall)/murder hole (ceiling)
07Bits of furBed
10Bones (humanoid)Brazier
11Bones (nonhumanoid)Cage
16Branding ironCatwalk
17Broken glassChair
19CandleCharcoal bin
21Cards (playing cards)Chest
22ChainsChest of drawers
23Claw marksChute
24CleaverCoat rack
25ClothingCollapsed wall
27Cold spotCupboard
28Corpse (adventurer)Curtain
29Corpse (monster)Divan
31DiceDoor (broken)
32Discarded weaponsDung heap
33DishesEvil symbol
34Dripping waterFallen stones
38Equipment (broken)Forge
39Equipment (usable)Fountain
40FlaskFurniture (broken)
41Flint and tinderGong
42Foodstuffs (spoiled)Hay (pile)
43Foodstuffs (edible)Hole
44FungusHole (blasted)
46HookIron bars
47HornIron maiden
52KeyLoose masonry
57MudMound of rubble
59Musical instrumentOverhang
60Mysterious stainPainting
61Nest (animal)Partially collapsed ceiling
62Odor (unidentifiable)Pedestal
63Oil (fuel)Peephole
64Oil (scented)Pillar
66PaperPit (shallow)
68Pipe (smoking pipe)Pool
71Pottery shardRamp
73Puddle (water)Relief
79SackSpinning wheel
80Scattered stonesStall or pen
81Scorch marksStatue
82Scroll (nonmagical)Statue (toppled)
83Scroll case (empty)Steps
85SlimeStuffed beast
86Sound (unexplained)Sunken area
87SpicesTable (large)
88SpikeTable (small)
91ToolsTrash (pile)
92Torch (stub)Tripod
95TwineWall basin
97UtensilsWeapon rack
99Wood (scraps)Winch and pulley
100Words (scrawled)Workbench


1Up to dead end
2Down to dead end
3-9Down one floor
10-14Up one floor
15-17Trapdoor plus ladder up one floor
18-19Trapdoor plus ladder down one floor
20Shaft up and down, one floor each way

Step 3 – Cleanup

These will inevitably be some dead ends, hanging corridors, and other weird odds and ends. Do your best to connect these where it makes sense, or just remove anything which isn’t adding to the dungeon. If you have an entire section of the dungeon which is a maze of dead ends, it should either be removed or you should make it make sense. In a cave, crevices in the rock might suddenly end. In a building, sections of the ceiling may have collapsed to block passages.

Step 4 – Encounters

The 4th edition rules have a bit of an advantage for generating random encounters. Because of the specifically denoted “roles” provided in the rules, you can build a diverse, balanced encounter by picking some random monsters with the right roles. By creating a “deck” of monsters, as detailed in the 4e DMG, you can generate all of the random encounters in a dungeon from a small library of level-appropriate monsters.

Most RPGs lack these specific monster roles, so replicating the 4e encounter deck is difficult in most other RPGs. Instead of creating an encounter deck with a grab-bag of monsters and traps, we can get the same sort of feel with a deck of pre-made encounters. These encounters can be any appropriate combination of traps and enemies that provides an appropriate challenge to the party.

Because using monsters of all one power level can be very bland and because it limits our options, I recommend using a sort of bell curve of difficulties. The majority of the encounters should be the appropriate difficulty to provide an average challenge for the party. Roughly 20% of encounters should be difficult, and 20% should be easy. If you want to have a sort of “boss” encounter, add an additional encounter that’s exceptionally difficult, and consider reserving it for late in the dungeon.

Random Encounter Types

d10Encounter Template
1-2Battlefield Control
3-4Commander and Troops
5-6Dragon’s Den
7-8Battle Lines
9-10Wolf Pack

Battlefield Control

The key component of the Battlefield Control encounter is an enemy with the ability to limit where and how the part can move about the field. Spellcasters and similar monsters make excellent choices for this encounter type. The secondary component is small enemies to take advantage of the party’s lost mobility to deal damage.


These encounters feature a single “commander” enemy, either an NPC of higher level than its troops, or a monster like an Aboleth or Mind Flayer which has minions of some sort. The troops typically do most of the fighting, but the commander is the real threat.

Beast’s Den

A solo monster on its home turf can be a terrifying threat. Pick something big, scary, and self-sufficient. Dragons are a good choice, as are Beholders, and other big, iconic monsters. Alternatively, a single enemy supported by environmental hazards or traps can be a good choice.

Battle Lines

These encounters feature one or more melee enemies, and one or more ranged enemies. A party of enemy adventurers can be a great fit in this encounter type.

Wolf Pack

A pack of weak enemies attempts to overwhelm the party by sheer numbers. Most RPGs have rules for minions/mooks/extras, but if your game doesn’t you can still use a cluster of enemies well below the party’s power level.