Perception is the ability to use your senses to detect and analyze objects and your environment.
A character not trained in Perception cannot succeed on tasks with a DC higher than 20 and any result they roll that would be higher than 20 is treated as 20.
Perception is used to oppose Stealth and certain Misdirection checks and can also be used to detect other scents, sights and sounds. The DCs for these are decided by the DM, but here are a few examples:
|Sounds of battle||-20|
|Garbage, fisheries, or other strong odors||-10|
|Smell of smoke||0|
|See visible creatures or objects||0|
|Hear normal volume conversation||5|
|Hear sound of normal walking||5|
|Hear whispered conversation||10|
|Hear weapons being drawn||20|
|Smell gun oil or honed steel||20|
|Identify ally by scent or sound||30 minus relationship modifier|
|Detect burrowing creatures||30 minus 5 per size modifier above small|
Detecting objects and creatures and opposed checks are modified by the following:
|Distance||+1 per square|
|Through closed door||+5|
|Through wall||+10 per foot of thickness|
|Creature making the check is distracted||+5|
|Creature making the check is asleep||+10|
|Target is invisible||+20|
Making a Perception check is a minor action.
A character is always picking up information through their senses even if not actively trying. Therefore, all characters has a stat that is effectively an ongoing Perception check known as Passive Perception. To calculate this, add 10 + your total bonus to Perception.
Your DM will record this number and, during play will compare it to the DC of things you might want to notice and let you know what you detect even if you haven’t asked for a Perception check.