Perception (Wis)

Use this skill to see or hear someone at a distance.

Check: The maximum distance one can see a Medium creature, assuming flat terrain and clear conditions, is 500 feet. Detail is impossible to make out – you can't tell the creature's race, what it's wearing, or what it's doing, for the most part.

The maximum distance one can hear a Normal sound (one person speaking in a normal tone of voice) is 100 feet. Again, specifics are impossible to make out – you can't determine individual words of identify the sound, just hear it.

At 3/4 max distance, the character can tell the creature's general size and shape, but exact identification is impossible unless the creature is very distinctive. Sounds can be identified if they are fairly distinctive.

At 1/2 max distance, the character can determine the creature's general type (humanoid, giant, etc.) and may even be able to tell specific race, if it's distinctive; size, shape, and color are all evident, but individuals usually cannot be identified. Large banners can be identified. The listener can identify most sounds.

At 1/4 max distance, individuals and smaller banners can be identified; broad actions (raising one's arms, drawing weapons, etc.) can be noted, but smaller ones (like pickpocketing) cannot. The listener can make out about half the words being spoken.

At 1/10 max distance, one can make out all but the smallest details – facial expressions, small movements, coats of arms etc. can all be seen. The rule of thumb here is that if something requires a Perception check to see normally (an earring normally hidden by a woman's hair, or the design of a tattoo on the back of a man's hand, for instance), it can't be seen at this distance. The listener can hear all the words clearly, and can identify the speaker if he knows who it is.

The DC for spotting a human-sized figure at any range up to 50 feet, assuming clear line of sight and adequate illumination, is 5. At 100 feet, and each 50 feet beyond this, the DC increases by +2, to a
maximum of 500 ft. (DC 25). Each 50 feet is considered a sight increment – like a range increment, but used for spotting purposes. Size modifiers for all creatures apply at any range.

The DC for hearing a Normal sound (2-3 people speaking normal voices) at any range up 100 feet is also 5.

Each size category larger than Medium increases the maximum range, and each size smaller decreases it (see Table 1).

Table 1: Sights

Size Sight Inc. Max Distance
Fine 2 ft. 20 ft.
Diminutive 5 ft. 50 ft.
Tiny 10 ft. 100 ft.
Small 25 ft. 250 ft.
Medium 50 ft. 500 ft.
Large 70 ft. 770 ft.
Huge 90 ft. 1170 ft.
Gargantuan 120 ft. 2250 ft.
Colossal 160 ft. 2720 ft.
Titanic 210 ft. 3990 ft.
Titanic++ 280 ft. 5880 ft.
Titanic+++ 370 ft. 8510 ft.

Range Increment: The DC for a Perception check is increased by +2 per range increment. For example, the DC to spot a troll (Large) 400 feet away would be 14 (-1 for size, +5 for distance).

Max Distance: The maximum distance something can be seen or heard. Beyond this point, no check, how matter how high, will succeed. Specific circumstances can increase the max distance, like a wind carrying the sound; these should be adjudicated on a case-by-case basis.

A creature up to Medium size, or a sound up to Normal loudness, can be seen or heard out to 10 range increments. Each size larger or louder increases the maximum – the larger or louder something is, the further away it can be seen or heard.

Table 2: Sounds

Loudness Sound Inc. Max Distance
V. Quiet 2 ft. 20 ft.
Quiet 5 ft. 50 ft.
Normal 10 ft. 100 ft.
Loud 25 ft. 275 ft.
V. Loud 50 ft. 750 ft.
Thunderous 100 ft. 1900 ft.
Painful 200 ft. 4600 ft.

Very Quiet (up to 20 dB): Whispering, an owl on the wing, a stalking cat.

Quiet (30-40 dB): One person talking in a low voice, a person walking on a soft surface, a normal voice in the next room.

Normal (50-70 dB): 2-3 people talking in normal voices, a rainstorm (no thunder), street traffic.

Loud (80-90 dB): 5-6 people talking in normal voices or 1-2 shouting, a horse galloping on dirt or walking on cobbles, a glass shattering, a metallic object being dropped onto a hard surface; distant thunder; a fireball spell.

Very Loud (90-110 dB): Many people (over 20) talking at once, or 5-6 shouting; a horse galloping on cobbles; a lion's roar, a large orchestra, a lightning bolt.

Thunderous (120 dB): A waterfall nearby; a thunderstorm directly overhead; many people shouting; a battle all around.

Painful (130+ dB): Most sonic spells. Sound at this level will cause hearing damage.

Lighting and Terrain: Lighting conditions and terrain play a large part in how easily and how far away a character can spot someone or hear something. Table 2 lists the modifiers for various environmental and lighting conditions, as well as a few miscellaneous circumstances that would apply a modifier to the check.

Note that "terrain" in this case can be applied to other circumstances. For instance, a crowd of people could be considered a forest – light, medium, or heavy depending on how many people there are. Likewise, a city full of close-packed buildings could be considered a medium or even heavy forest, whereas a small village, with the houses scattered but still somewhat obstructing sightlines, could be considered hilly terrain.

Table 3: Visibility Modifiers and Ranges

Condition Modifier
Target is moving1 +2
Target is trying to gain the spotter's attention +2
Target is raising a dust/smoke cloud 2
Environmental conditions Range Inc.
Bright daylight 10/10
Mist, light rain, light fog/snow (<1/2 inch/hour) 8/8
Dusk/twilight 8/10
Moonlit night (full moon) 6/10
Moderate fog, heavy rain 6/6
Moonlit night (half moon or less) 4/10
Moonless night, starlight 2/10
Heavy fog/blizzard/sandstorm 3
Terrain Dist. Mod.
Plains/desert4 +0 (100 ft.)
Hills -20 (80 ft.)
Marsh -40 (60 ft.)
Underwater -40 (60 ft.)
Forest, light -60 (40 ft.)
Forest, medium -80 (20 ft.)
Forest, heavy/jungle -90 (10 ft.)

1 Normal movement. If the creature is sneaking, the DC to perceive it is its opposed Stealth check.

2 A dust/smoke cloud is treated as being three size categories larger than the creature making it, so it can be spotted further away and more easily.

3 These conditions reduce all sight to 1d6+4 feet. Creatures and objects larger than Medium can be spotted slightly further away – 5 additional feet per size above Medium – but no details can be made out beyond the creature or object's general size.

4 Deserts with high dunes are treated as hilly terrain.

5 Since mountains cover the largest variety of terrain (from flat meadows to rugged hills and cliffs to winding canyons) it is best to apply the modifiers for another terrain type to the specific area.

Modifier: The modifier to Perception checks, which applies at any range, regardless of how far away the spotter can see or hear the target. These modifiers can also be applied to ranged attacks, at the DM's option.

Range Increment: The number of range increments that can be applied. The number before the slash applies to seeing targets; the number after it applies to hearing sounds. For instance, on a clear day, you can see out to the maximum range of 10 increments; at night, during a full moon, this is reduced to 6 increments. In both cases, however, sound is unaffected. The maximum range based on environmental conditions always takes precedence over size – a Huge creature can normally be seen 12 increments away during daylight, but this is reduced to 6 during a full moon.

Distance Modifier: This is the modifier applied to a creature's increment distance, based on the terrain. For instance, a Huge creature could be seen up to 120 feet away on a plain without penalty, whereas the distance is reduced to 60 feet in light forest. Likewise, the distance at which sounds can be heard is reduced, as the terrain muffles and distorts them.

If the terrain would reduce the range increment by half or more, then the distance modifier for size doesn't count - use the terrain modifier (the number in parentheses) instead. For example, a Colossal creature or Painful sound has a range increment of 120 feet; in medium forest, this would be reduced by 80 (which is more than half), so you would use the medium forest terrain distance – 20 feet per increment – instead.

Groups: Oftentimes, a character will spot a group of creatures on the move, or enemies will spot a party of adventurers. Either way, the same rule applies – if the creatures are relatively close to each other (i.e., they are gathered in a limited radius), they are treated as being a group, and are considered a larger creature for purposes of being seen. The same principle applies to sound – several smaller sounds are combined to make one larger "mass" of noise. In this case, use the size equivalency rules to determine the group's (or sound's) relative size (see below):

32 Fine = 16 Diminutive = 8 Tiny = 2 Small = 1 Medium = 1/2 Large = 1/4 Huge = 1/16 Gargantuan = 1/32 Colossal = 1/64 Titanic

For sounds, the size comparison is:

4 V. Quiet = 2 Quiet = 1 Normal = 1/2 Loud = 1/4 V. Loud = 1/8 Thunderous = 1/16 Painful

Basically, two creatures of a given size, or sounds of a given volume, equal one of the next larger size or volume. If two sounds are the same (two people chanting together, for instance) as opposed to different (two people talking at the same time), treat them as being one volume louder. For example, four people chanting in low voices (Quiet) would normally be treated as a Loud noise, but since they're chanting together, it's treated as a Very Loud noise.

Swarms are treated as single creatures, but are considered Medium. Larger swarms are treated the same as combining two or more creatures of Medium size - two equal a Large creature, four a Huge, etc.

Elevated Positions: A person standing in an elevated position (in a tree, on a tower/hilltop, flying, etc.) enjoys a much greater range of sight and hearing than someone on the ground, due to the lack of ground cover and ground-level atmospheric distortions (heat waves, e.g.) interfering with line of sight. Each 10 feet above the ground grants a +1 circumstance bonus to Perception checks to see things and ranged attacks, to a maximum of +10 to Perception and +5 to attack rolls. Each 100 feet above the ground lets someone see one increment further, to a maximum of +5 increments (for example, a Medium creature could be spotted 750 feet away instead of 500). These bonuses do not apply in conditions that reduce sight to less than 10 feet – fog clouds, sandstorms, etc.

By the same token, a creature in an elevated position (especially flying) is easier to see. The same modifiers apply to someone on the ground trying to see the target, but if the target has cover or concealment, these modifiers apply – someone standing high in a tower looking out an arrow slit, for instance, can see very far, but is hard to be seen in turn.

Water: While water distorts light waves, making things harder to see, it conducts sound very well (sound waves travel 3 times faster through water). All range increments and maximum distances for sounds underwater are doubled.

Telescopes: A telescope doubles all sight ranges, and all distances listed above for identification, etc. are likewise increased – so, for instance, one could spot a person up to 1,000 feet away on a plain, instead of 500, and identify him at 250 feet instead of 125. This bonus only applies in daylight conditions, however, unless the telescope is enchanted to grant the user the ability to see in the dark.

Action: Making a Perception check is usually a free action.

Try Again: Usually no, unless conditions change enough to give the character a chance to see or hear the target.

Special: Elves have a +2 racial bonus to Perception checks, +1 per 5 levels. Half-elves and halflings have a +1 racial bonus to Perception checks, +1 per 5 levels.

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