Dungeon Design 101

Table of Contents

by Guest Blogger Daniel “The White” LeBlanc

One of the most underrated yet important parts of DMing is the creation of dungeons for the adventurers to explore. Too often we focus on the story telling or interesting ways to run the fights, all the while ignoring the fact that the players need places to be in for the story to be told and the monsters to be killed. I use the term ‘dungeon’ to describe any setting that you, the DM, can come up with be it forest, swamp, cave or honest dungeon, built beneath an evil wizard’s tower. Like many, I used to agonize over each and every room, spending countless hours on each map I needed to make however, like everything else, minimal time is needed for preparation if you know what you are doing. This article shows a quick and easy way to generate dungeons quickly and easily. 15 to 20 minutes should be enough to get a playable dungeon.

First, a few materials you’ll need to get started.

1: Paper. While this seems obvious, some types of paper are much better than others. For organic areas with lots of squiggly lines normal paper is OK but these are hard to describe, for simplicities sake I suggest sticking to straight lines until you get used to everything, for this purpose grid paper is ideal. Grab a grid book from pretty much any newsagent or school supplies store; alternatively you can download customizable and printable sheets from many places on the internet such as http://www.printfreegraphpaper.com/

2: Pencils. Never, I repeat NEVER, write in pen if you make a mistake it is very messy to fix up. For most purposes a standard HB pencil will be fine but it is great to have some basic colored ones. A blue patch works much better to represent a lake than a circle with a note in it.

3: Misc. An eraser is a must for getting rid of those little mistakes you will inevitably make. A ruler helps for your basic straight line and a protractor makes the dreaded circle room much easier to draw.

4: Dice. Grab your dice bag and get ready to roll. Trust me, this will become clear soon enough.

OK, got your equipment… No? Why not? Grab them and meet me back here to make your dungeon. Trust me; I’ll wait for you… Oh, you’re back, good, time to get started.

I’m going to be assuming an average size dungeon which can be mapped out on a single sheet of A4 paper, for smaller dungeons only use a portion of the sheet, for larger ones use multiple sheets, easy as that. Start by dividing your paper into thirds, both horizontally and vertically, this gives you 9 sectors to work with and a sector of a few rooms is far easier to build than a whole dungeon. Pick a sector to start in, I tend to start at the top-left corner and work towards the bottom-right but the order is up to you. All the basics are now done and it’s time for the fun stuff. For each sector follow the steps outlined below.

1: Determine how many rooms in the sector and how big they are. Grab a percentile die and consult the table.

1-10: 6 small rooms
11-22: 4 small and 1 medium rooms
22-28: 2 small, 1 medium and 1 large rooms
29-40: 1 small and 2 medium rooms
41-49: 2 medium rooms and 1 small rooms
50-58: 2 medium and 1 large rooms
59-68: 1 medium and 2 large rooms
69-75: 3 medium rooms
76-80: 2 large rooms
81-90: 1 large room
91-100: 4 small rooms

2: What shape is each room going to be? Well it’s quite simple; in fact, it is just as simple as working out how many they are in a sector. Grab your percentile and roll for each room, note down each result as you get it.

1-5: Circle
6-15: Octagon
16-50: Rectangle
51-85: Square
86-100: Triangle

Yes, most rooms are going to end up either rectangle or square but trust me, describing and drawing them is much easier than the other shapes.

3: Last but not least you need to know exactly what size each room is going to be, until now all you have had for sizes is the vague description of small, medium and large. This is the longest section since you need to roll at least once for each room. As you roll the size of each room you can draw them in, either number each quarter of the sector and roll a d4 so see where the room lands or pick for yourself. I’ll also give some tips for drawing each style of room. All sizes are measured in squares of grid paper, it is up to you to determine what each square represents. I use each square as 5ft (so a small square room will end up between 10 and 20 feet on each side while a large one will be between 10 and 60).


By far the easiest room to roll and draw simply roll the dice to get the size of each side of the square.

Small: 2d2
Medium: 2d4
Large: 2d6


The rectangle is harder than the square to draw, but only because the sides are different lengths. Notably, it is possible to roll the same number for each side which pretty much turns the rectangle into another square, if you don’t want that simply re-roll one side.

Small: 2d3 by 2d4
Medium: 2d3 by 2d4
Large: 2d4 by 2d6


Well, that about wraps it up for the easy shapes, time for the harder ones. For the octagon you have two choices, either you can have the room a regular octagon (all eight sides the same length) or irregular (all sides can be different lengths). I honestly recommend the regular octagon for simplicities sake but if you want the irregular shape you’ll need to roll once for each of the first seven sides (the last one just connects the last gap). The numbers may seem small in comparison to the other shapes but an octagon 4 squares to a side is MUCH bigger than a rectangle 4 squares to a side.

Small: 1d2
Regular: 1d3
Large: 1d4


While there are many types of triangles, the easiest two to use are the equilateral and the right angled. For the equilateral, roll once and make all sides the same length. Place a dot at each corner and use a ruler to connect them. For the right angled one you need to roll twice. Place a dot in a corner, another one directly above it and another one horizontally next to it (the distances determined by the rolls). Connect the dots and voila, a triangle. Of course, if you want to make it complicated on yourself you can roll for each side and work it out from there but you will be kicking yourself when you have to describe the room later. Either choose which type of triangle you want to use or flip a coin, heads it’s equilateral, tails it’s right angled.

Small equilateral: 2d3
Medium equilateral: 2d4
Large equilateral: 2d6
Small right angled: 2d3 by 2d2
Medium right angled: 2d4 by 2d3
Large right angled: 2d6 by 2d4


Ahh the circle room, my old nemesis, there is a reason I have left this room to last and why it is the least likely result on my table. First, I hate drawing them, second I absolutely detest trying to get my players to visualize the room, let alone placing it on a battle board. The single easiest way to draw it is to grab a protractor, set the distance to however many squares you roll up and go from there. Failing that pick a midpoint and place a dot at the edges of where the circle will be and connect them up as best as possible.

Small: 1d2
Medium: 1d4
Large: 1d6

Well, what do you know? Your first sector is pretty close to complete, all that remains is to connect them up any way you want. Either you can run a large corridor through the whole sector with some smaller branching corridors or have the rooms connect directly to each other or any combination in between. Don’t forget that you can always leave a room or two connected only secret passages. With that out of the way, go back up to the top and do it again for each sector and connect the sectors in the same way you did each room in each sector.  Don’t forget to give at least one sector access to the outside world.

That about wraps it up, the hard part is done, the rest is up to your imagination. Is your dungeon a cave system? Is it well made or rough hewn? Maybe it’s a swamp with slightly shallower pathways. I suggest numbering each room for easy reference and writing descriptions on another sheet of paper. You need to think about what type of doors (if any) separate the corridors and rooms. Tables and ideas for traps, random encounters and treasure can be found easily with a bit of work, heck the treasure and random encounter tables are in the core rulebooks for most systems, or you can tailor each encounter yourself, or do what I do, decide on the important bits and randomize the rest. Remember, each table is only a guide, you can change the values or ignore them completely if you want, if a room needs to be a certain shape or size for your idea to work the put it in. Maybe you like circles more than I do or you want a more organic looking dungeon, add a few numbers to the circle result and take them away from something else. Maybe you hate triangles, get rid of them, don’t let a random table ruin what you are trying to achieve. Your decision, as always, is final.

16 thoughts on “Dungeon Design 101”

  1. i have just started my first campaign with a group of my friends, and i have been trying to create my dungeon from bottom up. Of course i manage to finish it just the day before i find this site :P
    i want to encorperate a few set of dungeons as this is the first real campaign for many of my players, so i want to give them the feel for the real classic dungeon crawl. now with this guide i won’t spend four days makeing just one dungeon.
    So i bow down and praise you O dungeon god lol
    seriously though thx you saved me for future events

  2. I found a new use for your plans. I have used your plans to also make a entire town. i just used squares and rectangles for buildings and put 4 octagons at the far corners for watchtowers. each of the 9 sectors became a block and then i made the houses. i kept them low. as it was a small town ad the building is “spuratic” to put it faintly. (really just poor planing.) I made streets 20 ft wide on each of the folds and kept buildings at least 5 ft (one sq.) apart and just went from there. it also helps if you need a floor plan for one of the said houses. it makes building rooms alot easier. though keep in mind the scales don’t make a bit of sense. like if the house is 20ft X 30ft on the outside it may be like 60 X 50 on the inside. I made up for this by making the magority of the town magic users so that this can be explained by the insides of the houses being built into an extradememnional space or that the outside of the house was compresed while the inside stayed the same. it works and is as far as I know a fine explination. it fits my purposes and well I can always use the “my word is law” line on my players. Well that’s my system, hope you enjoyed my little speal and well I’ll be off now. [large footsteps fade into the distance]

    Your Friendly Brass Dragon,
    Elderon Analas

  3. I know it may sound like some sort of blasphemy, but I have been making maps using simple spreadsheets:

    1) I get the grid lines I want,
    2) I can size the squares as I want,
    3) I can colorize dungeon floor squares versus dungeon walls for example, as well as roads/trees/grass/rocks/water for outdoor areas.
    4) I can label in other items such as tables, coffins, etc. as needed,
    5) I can include labels, notes or comments (i.e., N/S/E/W) as well, and
    6) I can save/update the map in a more-or-less permanent file format.

    The best part is that I can then print out each page of the map with the grid labels so that when I tape the pieces of the map together the grid labels are present throughout the map, not just on the outside edges (Laugh now … wait until you get older and your eyes start to go … )

    In future versions I am considering cutting and pasting in jpeg pictures of items like tables, coffins, etc. Obviously I don’t get any squiggly or unusual (non-grid) lines, but this has worked very well for us.

  4. @ BlueWolf. That’s great, I know a few people in your shoes. A couple of the other guys in my group who I share the DMing with never run dungeons that they haven’t found on the net for that exact reason. I’ll probably end up sharing this with them if I keep getting positive comments like that.

    The fun thing with doing up dungeons using methods like this is the funky designs that come up that you might never have thought of yourself. One sector I rolled up a few dungeons back had 6 small square rooms each 2 by 2, ended up being a tunnel with the rooms being wider bits, usually with traps or monsters in them. Got the players very paranoid. You also get funky things happening if you randomize your treasure tables and encounter tables, my last dungeon (players were all level 2) had one room spawn a set of half-plate and the next room spawn a rust monster… the fighter hated me :D

    If I get a chance and if you guys think it would be a good idea I might throw together something on populating your dungeon since that can take almost as long as drawing it up if you make yourself think about every little detail.

  5. When it comes to drawing out dungeons, I’ve always had trouble deciding how it should look so I’d try to avoid running dungeons games and mainly create games that take place in above ground terrain. With this article, now I don’t have to worry and my players can now fight Drow. :D

  6. COOL :D

    a few years ago I had a blast rolling up a random dungeon using the 1st ed. DMG :) I never finished it (it got huge) but holy crow that was fun….I think I’m going to have to try it again with your system now :D thank-you!

    (I don’t know if you’ve found this, but I found when stocking my random dungeon with treasure I got really creative with goodies, and particularly magic items….)

  7. @Camwyn… Yes, yes I did, good spotting, my bad.

    @Palomon. Add em together. 2d2 resulting in a 1 and a 2 = 3 squares. It may seem small but you get heaps of space to work with by the time you have a few rooms placed.

    Thanks for the comments guys, keep ’em coming. Every comment helps me and others with our writing and every question asked lets me give further insight. I love the feeling I get from imparting knowledge to others :D

  8. Great advice! My only question is when you’re describing how to roll for the measurements of the room, do you add up the dice or do you use them like a percentile die (i.e. 2d2 results in a 1 and a 2 = 12 squares)?

  9. “The single easiest way to draw it is to grab a protractor,..”
    Think you meant a compass – two arms with a pencil, as opposed to a protractor – half-circle ruler (used to measure angles, not draw them).

    Personally, I don’t draw maps until it’s game-time and then it’s usually on a battle mat. I often just describe the room and let the players draw it.

  10. Nah, I wrote a Visual Basic character generator for 2nd ed in the late 90’s.

    OH and YEA THEY PUBLISHED ME!!!!!! AWESOME. I wanna hear everyone’s comments :D

  11. Very old school! I think I wrote a program in BASIC back in the 80s that did this exact kind of thing. What, didn’t everyone?

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