How does the Stealth versus Perception check work in combat?

Question

My rogue tries to hide with his bonus action to gain advantage on his attack. Thus the action order is move (5-10ft) behind total cover, Hide (bonus action - roll stealth check), move (5-10ft) to get LOS on target, shoot crossbow (Action) and then maybe move again.

What normally happens is: my DM rolls an active perception check versus my active stealth. Is this correct? I thought active perception checks took an action.

Another scenario is looking for hidden/invisible targets (in combat). When its my turn, do I need to spend an action to look (active perception check) for a hidden/invisible target? Could I use my passive check for free? I know the target is around (because it just attacked and went hiding/invisible).

Please confirm or let me know the RAW way to perform perception versus stealth checks in combat.

Answer 1

RAW your opponent should not get a free active Wisdom (Perception) check.

You use your action to Hide, you are now Hidden and some creatures can see you and some can't.

In general, RAW if you approach someone in combat they see you. PHB p.177:

In combat, most creatures stay alert for signs of danger all around, so if you come out of hiding and approach a creature, it usually sees you. However, under certain circumstances, the Dungeon Master might allow you to stay hidden as you approach a creature that is distracted, allowing you to gain advantage on an attack before you are seen.

RAW if their passive Wisdom (Perception) equals or exceeds your Dexterity (Stealth) check, they see you (don't forget to apply disadvantage [-5] if you are lightly obscured inc. dim light). PHB p.177:

When you hide, there’s a chance someone will notice you even if they aren't searching. To determine whether such a creature notices you, the DM compares your Dexterity (Stealth) check with that creature’s passive Wisdom (Perception) score ...

If neither of these things happen they must guess your location and make an attack (with disadvantage) at that location, if they guess wrong they will automatically miss. PHB p.195:

When you attack a target that you can’t see, you have disadvantage on the attack roll. This is true whether you’re guessing the target’s location or you’re targeting a creature you can hear but not see. If the target isn’t in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target’s location correctly.

Or they can use an action to Search for you and engage their active Wisdom (Perception). PHB p.192:

When you take the Search action, you devote your attention to finding something. Depending on the nature of your search, the DM might have you make a Wisdom (Perception) check or an Intelligence (Investigation) check.

This is only fair, you used an action to hide, they need to use an action to seek. Hide & Seek ... someone should make that into a game ...

Answer 2

The Search action is not the same as an "Active" Perception Check.

The primary reason for the distinction between "active" and "passive" perception checks is to give the "agency" in the roll to the active party and to make it less obvious to the players what is happening beyond their player's perception. If stealth v. perception contests were always handled with an active perception roll, the players would be always aware that secret doors and ambushes were nearby even as their characters remained oblivious and players would never get to roll to see if their rogue sneaked past the dragon - that roll would always be in the DM's hand. Reversing the process isn't any better.

The DM has discretion over whether to call for a Stealth v. Passive Perception, Stealth v. Active Perception, or set a DC for an Active Perception roll. Most DMs will choose according to the Rule of Fun.

The Search action will usually provide an opportunity for an Active Perception check, but it is not a requirement.

Key Point: Rolling against an "Active" vs. a "Passive" check barely budges the probability.

A Passive check is the equivalent of simply assuming the character rolls a 10 on his d20. Advantage and Disadvantage are somewhat exaggerated with the passive check (the "correct" value should be between +/-3 and +/-4), but since this works both ways, it really doesn't much budge the overall probabilities. Overall, granting an Active check instead of a Passive check is the equivalent to granting a +0.5 to the character's roll. It does make a practical difference when the skill modifiers are very different, since allowing an Active check does give some hope to the character who is terribly overmatched.

This is why the book seems so vague regarding which to use. It really doesn't matter, probability-wise. As the Rogue Hides, he makes a Stealth Check, and it doesn't really matter much whether his target value is the Passive Perception of the guard or the guard's Active Perception plus a d20. The idea that making it an Active check somehow gives the guard something for "free" is misguided.

Answer 3

"Active" and "passive" checks have nothing to do with character actions; they are related to player actions.

A passive check means that the player was passive and did not roll any dice. It is for situations where the player doesn't want to roll lots and lots and lots of dice. For example, "make a WIS/Perception roll for each 10 feet of dungeon passage, for the next half a mile of caves."

They can also be used by a GM to surprise players. If a GM says "Make a WIS/Perception roll" then players are going to be on their guard; using a passive roll means that the players are just as surprised as their characters.

In the example in the question, those in combat do not need to spend an Action to be aware as it is assumed that all combatants are constantly looking around for threats.

Spending an Action in combat to examine something might be required if the examination requires more than just a look. For example, tapping over a wall to find a secret door. For example, feeling around a statue to find a hidden lever.

Answer 4

Active Perception checks in combat DO require an action, specifically, the Search action.

PHB p. 174

Ability Checks ...The DM calls for an ability check when a character or monster attempts an action (other than an attack) that has a chance of failure.

Therefore, if there is no action, there is no ability check.

Also, you can't be hidden if the enemy knows your position. So if the tactic you describe involves you ducking behind a barrel in the middle of a tavern and attempting to hide, you are not "hidden" but you are "unseen"

Answer 5

The Legendary actions of any adult dragon suggest the idea that active wisdom(perception) checks do cost actions.

"Legendary Actions

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.
Detect. The dragon makes a Wisdom (Perception) check. (Adult black dragon. D&D beyond app; MM p. 87)

Answer 6

The following is my understanding of Perception checks to see/locate creatures that are hiding based off this post.

As a hide action, you make a Dexterity (Stealth) check. As long as you remain in hiding, your check must beat the opposing creature's Passive Wisdom (Perception) score. If you are hidden, you are unseen and unheard. Thus the creature does not know your exact location but may know a general direction based on the last time you were not hidden.

In combat if you are hidden from a creature and "come out of hiding and approach a creature, it usually sees you." To remain hiding you must remain unseen and unheard. The rules for Hiding says that "under certain circumstances, the Dungeon Master might allow you to stay hidden as you approach a creature that is distracted."

I would say as soon as you stepped out from behind total cover you may have just become seen and loose being hidden. To determine whether the creature sees you or is distracted I would role an Active Wisdom (Perception) check against the Dexterity (Stealth) check you made when you took the Hide action.

On the flip side, an unseen creature and a hidden creature is two different things.

A unseen creature, such as one in "darkness, opaque fog, dense foliage," or invisibility has advantage on attacks against creatures that can't see it, and those creatures have disadvantage on attacks against it. You can determine the location of an unseen creature through noise, smell, or other senses.

A hidden creature can't be directly targeted. The attacker must choose a space it thinks the creature is and because the creature is also unseen the attack is made with disadvantage.

In conclusion, I would say the DM can roll or have you roll an optional Active Wisdom (Perception) check when a hidden creature comes out of hiding or does something to give away its position to determine if others are distracted or not. Also, if a creature is actively searching for a hidden creature using the Search action, use an Active Wisdom (Perception) check. In all other cases use the creature's Passive Wisdom (Perception) check opposed to the Dexterity (Stealth) check made when the Hide action was taken.

If an unseen creature does not take the Hide action, its location can be deduced through the other senses without taking additional actions.