Random Dungeon Generator
Roll a complete dungeon level on a 5-ft grid: an entrance with stairs, themed rooms (libraries, shrines, barracks, flooded chambers, ossuaries), corridors with doors and locked doors, a few traps, and a treasure room at the far end. Tweak it square by square, then take it to the table.
Drawing the map…
Pick a tool above to paint terrain, drop props or tokens, and remove what you don’t need. Each square is 5 ft.
Export for your table
Map key
Read-aloud writer
How a dungeon is carved, step by step
The generator uses binary space partitioning (BSP), the same technique behind the levels of classic roguelikes. It is why the rooms never overlap and why every room is reachable. Step through it on a real seed:
1. Split the space
The map is cut in two, then each half is cut again, alternating direction when a piece gets long and thin. Pieces smaller than 8 squares stop splitting. The result is a tree of rectangles.
Tips for running a generated dungeon
Read the map key before the session and give each room one sentence of purpose: who built it, who lives there now. A dungeon feels designed when rooms relate to each other: the barracks sits near the entrance, the shrine near the lair. Swap themes by removing props and placing new ones.
Keep the corridors in mind as battlefields. A 5-ft corridor lets only one Medium creature fight abreast, which makes a single fighter a wall and a fireball a disaster. The loop corridor is where clever monsters flank a party that thinks it has secured its rear.
Questions game masters ask
What is a random dungeon generator?
A tool that builds a dungeon layout from rules and a random seed: rooms, the corridors between them, doors, traps and features. This one outputs a gridded battle map you can play on directly, not just a sketch.
Are all rooms connected?
Yes. Binary space partitioning joins every pair of sibling areas with a corridor, so there is always a path from the entrance to the final chamber. One extra corridor creates a loop for flanking.
How do I make a bigger dungeon?
Raise width and height up to 60 × 60 squares. More space means more splits and more rooms; 40 × 30 gives around six to nine rooms, 60 × 60 around twenty.
What do the red dashed squares mean?
Traps. The gold-studded doors are locked. Stairs up mark the entrance; stairs down, in the final chamber, lead to the next level.
Can I stock the dungeon with monsters?
Use the encounter builder with the Dungeon setting to roll a balanced group of SRD creatures, and the read-aloud writer under the map for boxed text.
More tools for your prep
- Battle map generatorAll five map types, editor and exports.
- D&D map makerPaint your own map on a blank grid.
- Tavern map generatorCommon room, bar, kitchen and storeroom.
- Cave map generatorNatural caverns with pools and stalagmites.
- Forest battle mapsTrails, streams, clearings and undergrowth.
- Throne room mapsDais, pillars, carpet and side doors.
- Ready-made battle mapsPick a finished map and download it.
- Encounter builderCheck 5e encounter difficulty by XP.
- D&D gridPrintable grids and diagonal movement.
- Roll20 & Foundry guidePixel sizes and import steps.