D&D 5E Rolling for Passive Perception


He / Him
I'm thinking of trying out something strange as a DM regarding Passive Perception.

As it is, I use Passive Perception in two ways:

1) When a character enters a setting, they perceived everything their Passive Perception would allow: hidden creatures, treasures, etc. Usually for secret doors and traps I give big clues and invite the character to look closer.

2) When a character rolls a Perception check, their Passive Perception is their floor- the lowest result they can get. If they roll below their Passive Perception, I just use their Passive Perception.

This does, however, make adventure design a little weird. In a way, I have to think of what a realistic DC would be for spotting something, but at the same time I just know flat out some of the characters are going to be able to beat it with their Passive Perceptions.

For example, in next week's adventure the characters are going to enter a dungeon room with a trap: a net will fall, and two flying swords will attack.

If I set the DC of spotting the net at, say, 14, I just know two characters will see the net. Why put a net there at all in that case? If I set it at 18 then no one will see it, but is that realistic? And why use Passive Perception at all if I'm just going to juice all the DCs?

So what I've decided to do is to roll during the session to set the Perception DC. Rather than preplanning a DC of 11 or 14 or 16, I'll write down +1 or +4 or +6. Then, when the characters enter the room, I'll roll for it and note the DC. Maybe I'll roll super low and everyone will see it. Maybe I'll roll super high and no one will. But either way it reduces my own meta-game thinking when planning the adventure.

Plus it's fun to roll dice, and I love random elements in adventure design.

So what do you think? Am I crazy? Do you do something similar, or is this just not a problem for you?

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I do precisely this, and I'll do you one better: passive knowledge checks. If there's details about a room or object the PCs could reveal with sufficient History, Nature, Religion, Arcana, etc, do the same transformation to give each fact an "obscurity bonus" and roll that against the PC's passive in the same skill. Then, instead of probing for more information, you can provide it outright as soon as they interact with those objects.

Ideally, this will make the PCs occasionally feel very clever when you foreground "your knowledge of blah/studies with the wizards/work in the Chantry informs you of this" and it will speed up play by pushing them to declare proactive actions that will change/reveal more about the environment.


As a DM, I've never had much issue with deciding a DC for what PCs might or might not notice.

However, that isn't what passive perception is for, the way we use it. "Looking" to notice something is ALWAYS an "active" roll. The players have to tell me, "My character is looking for any signs of x, y, or z." Otherwise, I simply describe the general area (using clues in a fashion you do).

Passive perception is simply the DM saying, "I don't want the players to know by telling them to roll" or "I know the PCs are actively looking for x, y, or z; so I'll go with the roll of 10 plus bonuses for each PC."

The idea of using Passive Perception for a "floor" isn't what it really is (or should be IMO) used for. The concept of "passive" (as in not "active") would not imply "average" effort, but rather a "minimal" effort. For that sort of Passive Perception, we would use a base of either 5 or 7ish, instead of a 10. We call this "Awareness" and not Passive Perception.

All that being said, I understand you issue with having set DCs and Passive Scores. Used in such a way, the same PCs tend to discover things before the PCs will lower scores, who miss more. Another option if this is annoying for you would be to make "searching" or "noticing things" a group check instead of using Passive Perception.

As far as feeling you are meta-gaming your adventure design, all I can say to that is "don't". 🤷‍♂️ The adventure is planned according to the world design, not the PCs. If a secret door is very well-hidden, set it to DC 20, for example. Then, passive 18's won't spot it unless the character searches for it and gets to actually roll. Then with their +8 bonus, they will have to roll a 12 or better. Another PC might be able to help, granting the first PC advantage, etc.


Magic Wordsmith
Unless it's a contest, pretty much all ability check DCs in my game are 10, 15, or 20. I also don't have much of a clue what the PCs have on their sheets. I don't really pay attention to it. After awhile, I might be able to guess which is the more perceptive character, but honestly I might get that wrong. I run or play in enough games that it all blends together for me.

Further, in a dungeon crawl, I have a more structured way of doing things typically. While traveling the dungeon, you're either keeping watch for lurking monsters OR traps OR secret doors OR drawing a map, etc., not all of the above. The players have to choose and also be in the position in the marching order to notice any threats (e.g. in the front rank, usually). If the players decide they want the characters to explore an area more thoroughly, then we'll go into rolls, if the approach to the goal has an uncertain outcome and a meaningful consequence for failure. Often that consequence is no progress and a loss of time - time which is counting down to doom or wandering monster checks. Sometimes it might be progress combined with a setback (and still a loss of time).

So in your example, even if I did know those 2 PCs could notice my DC 15 net trap, they'd still have to choose to be searching for traps (with the opportunity cost of being surprised by the flying swords, if the swords are sneaking) and also be in the right position to notice them at all. Otherwise, they have no chance of noticing the trap. Taking away the "always on radar" in favor of meaningful choice works well in my experience.


I think that sometimes, skill checks are unnecessary, the character just succeeds at X because they're good enough. So the party scout spots the trap? Great. This isn't a negative. The player feels like their character is kicking arse. It can also put the players on notice that this is a dangerous place, adding to atmosphere. There's even the slight chance some other characters will blunder into what is, to the scout, obvious. These are all net gains.


Guide of Modos
This is easy: passive checks don't belong in the game. They're a holdover of 3e ( and probably 4e later) groupthink. Examples, from the 5RD:

  • Searching a room over and over. When is the last time you looked in your glove compartment "over and over" to finally find your registration, or lip gloss? It's either in there, or it isn't. And you're either going to find it (eventually) or you won't. In all of these cases, it's easier for the DM to ask for a roll or two than to worry about what your passive perception is and whether the given DC accurately reflects how the passive perception should behave.
  • Spotting a hidden monster. This is the assumption, apparently, that a surprise will be ruined if the DM asks a PC to "roll perception," though there is no obvious threat - and inadvertently reveal the threat in the asking. The PCs will detect the monster either before or after it wants to be detected, otherwise it's effectively a non-encounter. So why not just ask the PCs to roll? If they "succeed," they've detected it before it reveals itself. If they " fail, " they don't notice the monster until it wants to be noticed. The DM request shouldn't happen until the PCs are located where the surprise round could go either way.

From OP:
- PCs enter a room with a hidden net. They're welcome to " look for traps" wherever they stand, but the further they are from it, the higher the DC. If a PC beats the DC, great! Net identified. That doesn't necessarily reveal the release mechanism, though. If they don't look, they get a chance, or "active" roll, to notice something right before it triggers. There's no surprise wasted by calling for the check, because failing the check means getting caught in the net.

But if more rolling floats your boat, have at it!

Edit: @DrunkonDuty nice pun!


Moderator Emeritus
It has never been much of an issue for me because even if I know the characters' passive perception (which I don't, I have them written on a post-it in easy view during gameplay but I have not memorized them), what I don't know is under what conditions they will be perceiving or not. . . for example, players love to live by darkvision alone, which makes their passive perception lower by 5! Maybe they will light a lantern, maybe they won't Maybe they will rush through there chasing (or being chased by) monsters and won't have much chance to notice the net until it is too late. So I go with the number that makes sense to the situation and can still be surprised. And if they do spot it and avoid it or pause to plan how to handle it, I consider that a win too.


Mod Squad
Staff member
If I set the DC of spotting the net at, say, 14, I just know two characters will see the net. Why put a net there at all in that case? If I set it at 18 then no one will see it, but is that realistic? And why use Passive Perception at all if I'm just going to juice all the DCs?

Great questions.

The players spent some of their build resources on having that ability. Sometimes, it should actually just work, you know? So, why put the net there at all?

1) Because you don't know that the characters with the higher Passive Perception will be the first ones in the room.

2) To make it sometimes worth the effort for the players who made those build choices.

Do you do something similar, or is this just not a problem for you?

Not long ago, I was playing a gnome battlesmith artificer, with a Passive Perception of 16, Passive Investigation of 24. The guy was freakin' Sherlock Holmes. No clue went unfound, no trap undiscovered. The GM was fine with it, it was a shtick he could play to - it allowed us to fast forward past "what do you know?" which isn't the interesting question anyway, and got us quickly to "So, what are you going to do about it?" which is a much more interesting question.

If you want to roll, just don't use passive perception. Let the players roll rather than you, they enjoy it more.

The whole concept behind passive checks are to reduce the amount of rolling.

Next, just because someone makes a passive check, doesn't mean they get the same information as if they made an active roll. I just give them a clue. "As you look into the cave, you get a tingling on the back of you hand, something is wrong..." Then they get to make an active perception check to see if they notice the net on the ceiling. But even if they don't, they know something is up and they slow down. Otherwise every room, every corridor is at risk of becoming a "We tie off with a rope, I use my ten foot pole to pre on each stone on the floor. I shine my lantern at the ceiling and look for nets...." That becomes tedious and boring very quickly.

PP tells the party (who have invested int eh skill) when to slow down, and when they can just move on and get to the fun stuff.

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