D&D 5E Dungeon Length: How long does it take?

How do you determine your dungeon's length? What tool(s) do you use to predict how many hours (or sessions) your dungeon takes to complete?

To elaborate: I'm fairly new to DMing 5th Edition. Anyways that being said, how do you determine your dungeon length? I don't just mean physical size but I'm also talking how many encounters populate your dungeon. Combat could slow it down, or even a difficult puzzle. I'm just looking for a general answer or rule of thumb based on your experience.

Even with decades of experience, it's really hard to determine how long an adventure will take IRL. Because of this I don't even try, but have each adventure go for multiple sessions as needed. I simply watch the time, and look for a good time to wrap up a session. As a rule of thumb, don't start a significant combat with less than a half hour to go. You'll probably be able to finish it, but it might push you over your time limit a little.

If you're wondering about overall length, I have two different methods, depending on the campaign type. If I'm running a sandbox game (where the world is disconnected from PC abilities), I usually design the dungeon, then populate it with whatever makes the most sense. This creates more challenge for the players, because it may be quite harder than the default assumptions. If I'm designing an adventure specifically for the PCs, I figure out how much experience I want to give out, and build the encounters with that budget.

A quick word about puzzles and trick. Never build an adventure where the players MUST solve a puzzle or overcome a trick. Not only does the grind the session to a halt, but it can ruin the adventure if the party can't figure it out to continue. Also, it's advisable to have an ability check prepared in advance that will give a hint on how to solve a puzzle (optimally, you want multiple hints for multiple successes, but not all puzzles will work well that way).

My 11-layer town-to-dungeon campaign took twenty 4-hour sessions to complete. Mostly combat and exploration, some social. Perhaps 30 minutes of each session was spent on town and wilderness, plus short breaks. So about 70 hours to do 120ish areas maybe.

I have a one-shot dungeon I'm running now with 16 areas, again mostly combat and exploration. So far two groups have tried it. The first group cleared and/or explored 6 areas. The second group managed to squeeze in one more than the first group. This is also about 3.5 hours of play.

It depends greatly on the style of the game, your players' preferences, what you decide to put into the dungeon, and the significance of the dungeon to the plot.

A clear-objective abandoned dungeon populated by unrelated squatter monsters and assorted hazards can be cleared a *lot* faster than a hidden-objective occupied dungeon with organized inhabitants and opportunities for side objectives such as intel-gathering. Even slower would be a dungeon with multiple sets of competing occupants and mutually-exclusive objectives that have to be learned about and prioritized during play.

To put it more simply... a dungeon that represents only a sequence of combat encounters will be much faster than a similarly-sized dungeon that involves exploration, social interaction, and/or party decisions/dilemas on what to do next.

I no longer run big dungeons like I did in the past. Most of my dungeons are based around the Five Room Dungeon concept.

Here's a quick overview: https://roleplayingtips.com/rptn/rpt156-6-methods-making-dungeons-interesting/

It's not five literal rooms, but rather five concepts to put in that give you a fun and varied experience without it becoming a grind.

Room 1: Entrance And Guardian
Room 2: Puzzle Or Roleplaying Challenge
Room 3: Red Herring
Room 4: Climax, Big Battle Or Conflict
Room 5: Plot Twist

While these aren't linear, I believe in making character choices meaningful. Having to work through a section of "do you go left or right" without any context or meaning isn't what fires up my table - they'd rather "you explore this wing, full of broken down rooms filled with the remains of furniture savaged by time and little else. The dust however shows recent tracks of large claw marks and the pungent smell of ammonia permeates many of the rooms."

Showing these aren't literal rooms, a "room 2" might be a whole maze, but instead of asking direction I instead have the players narrate how they are getting through it and then run it a bit like a skill challenge but also taking into account other resources used (spells, etc.) and strategies (right-hand rule, chalk marks, etc.) to give them a roll to determine how many hazards/encounters they will end up encountering on their way through.

From a length perspective, I usually plan about 3 (weeknight) session for this, 4 if there's moral decisions to be made as my group can have a wonderful hour-long debate on what is the right things to do. (They once ambushed a group that was working at cross purposes to them but not evil, defeated them, then spent the rest of the session debating what to do, ultimately letting them go but taking their supplies so they would be delayed and telling them that they let the druids know about them who might come to kill them.)

I prefer that my dungeons take between 1 and 2 sessions, but my players play very long sessions (7 to 8 hours).
I recently posted a guide on dungeon theming, called Fire and water: Designing themed dungeons. That dungeon is 3 maps long, where each map contains about 7 rooms, without pointless filler (you can check out the maps in the thread). The players got till the end of the second map in one session, leaving the last part of the dungeon for our next session. In my opinion that feels about right. The dungeon has a fair mix of exploring, roleplaying, and a few fights.

I'm often a bit surprised by how many battles people cram into their dungeons. This dungeon of mine has 7 fights, but the players skipped most of them, and had only 2. And that still felt like a fair amount of fighting. Especially given the size and difficulty of the boss battle.

Triumph_Fork said:

How do you determine your dungeon's length? What tool(s) do you use to predict how many hours (or sessions) your dungeon takes to complete?

To elaborate: I'm fairly new to DMing 5th Edition. Anyways that being said, how do you determine your dungeon length? I don't just mean physical size but I'm also talking how many encounters populate your dungeon. Combat could slow it down, or even a difficult puzzle. I'm just looking for a general answer or rule of thumb based on your experience.

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You're asking for distilling something MUCH more complex into a sound byte. So here's my take based on experience with my group:

A 4-hour session will contain 5 encounters, which may be involved combats (typically breaking out map & minis and/or bothering to roll initiative for), extended role playing situations like tense negotiations, and more involved exploring scenarios like room traps, major puzzles, or skill challenge scenarios.

Running D&D is like herding cats, so get used to plans going awry. 5e combats are designed to go quickly, and there's an expected number of encounters each level. So, you should be able to run a couple of combats per hour - but that could vary wildly, harder combats may take longer, /larger/ combats (more enemies) certainly can; and exploration can go fast or slow depending on how the party reacts.
At 1st level 4 hard encounters (though you'd probably want to do more easier ones) gets you to second level. That doubles at 3rd, and levels off at around 10 until 10th. So if you place the equivalent of 16 hard encounters in a dungeon, then a party who completely clears it will be 4th level. That's as good a yardstick as any.

Or you could just have an idea for a dungeon and stock it appropriately and not worry about any other sort of 'should.'

I don't typically like to run "super-dungeons". If it can't be reasonably hashed out in 1-2 dedicated sessions (that is, sessions where people arrive on time, come prepared to play, and keep their heads in the game), I don't think it's worth stretching out much further. Now, I run longer-than-usual sessions at 6-8 hours every other week, some some of your mileage might vary to 2-4 sessions of 3-4 hours.

I usually expect a dungeon to take 1-5 in-game days, depending on the overall size and complexity. With 5E, that typically means 3-15 encounters (I typically run 2-3 hard to deadly encounters per "day" with some puzzles mixed in). I design places that allow players to get rest...but they typically involve significant encounters to clear them out. IE: you might be able to all squeeze into the old prison cells, but that could be a serious risk if you're found. If you want the nice big prison courtyard, you're gonna have to clear out the goblins.

The "straight to the end" in my games should typically be 1-2 sessions. Because really IME, people get bored in dungeons (and I get bored running them).

Don't build a dungeon to meet a length, build it to fill a story.

Come up with a story that requires the heroes to venture into a dungeon, then build the dungeon that serves that story. If the story lends itself to a short dungeon - fine. If it is better served with a long dungeon filled with warring factions, complex traps, and ninja monkeys - well, go for it. Let the story dictate.