Darkvision mechanics

See also: Sight mechanics

 Darkvision is a passive feature that changes how natural darkness affects a creature. The related passive feature  Superior Darkvision is equivalent, just with a longer effective range. There are also some other passive features with a similar or equivalent effect. This page explains some details pertaining to such features and the related gameplay mechanics.

Apparent sight vs. combat mechanics

The game uses two different variables to handle how a character 'sees':

• ActiveCharacterLight: This determines the range of the visual cone of light emitted from the player character in dark areas when that character is selected, to indicate what they can see and provide player immersion. It can only be gained from one source at a time; if a character has multiple sources of it, then only the first applies.
• DarkvisionRangeMin: This is the value that is actually used in combat mechanics. It can be granted from multiple sources, in which case the highest value takes effect.

Range

Darkvision can have a custom range per creature, or rather, per source of Darkvision. However, the standard range, if the game's code does not override it, is 12 m (40 ft) for  Darkvision and 24 m (80 ft) for  Superior Darkvision. This is typically applied as both ActiveCharacterLight and DarkvisionRangeMin, though some atypical sources of Darkvision may only set one of the two variables for the affected creature.

A creature lacking a source of Darkvision still has a "minimum detection range" of 2 m (7 ft), within which neither possessing nor lacking Darkvision has any impact on combat. This range can be increased to 5 m (17 ft) through the passives  Deathbringer's Sight and  Murderous Sight, which then acts as a source of Darkvision in combat against creatures as long as the attack range is greater than 2 m (7 ft).

Impact on combat

When a creature has Darkvision, the game effectively alters the obscurity level of other creatures for that creature, provided that the other creature is within DarkvisionRangeMin. This affects stealth, and can also add a source of  Advantage or  Disadvantage on attacks:

• Attacking from Shadows: If the attacker has Darkvision and the target does not, and the attacker is  Heavily Obscured, this counts as a source of advantage for the attacker. This also works if the attacker has a longer Darkvision range than the target, and is far enough to be outside the target's Darkvision range, but close enough that the target is within the attacker's Darkvision range.^[verify]
• Too Dark: If a character lacks Darkvision, or the target is beyond their Darkvision range, and the target is Heavily Obscured, this counts as a source of disadvantage.

Racial Darkvision

The following table shows the Darkvision range granted by a creature's race.

Races	Range	Notes
Dragonborn, Githyanki, Halfling, Human	Effectively 2 m (7 ft)	Though these races don't have Darkvision, melee range always counts as visible.
Dwarf, Elf, Gnome, Half-Elf, Half-Orc, Tiefling	Darkvision – 12 m (40 ft)
Deep Gnome, Drow (full-elf only), Duergar	Superior Darkvision – 24 m (80 ft)

Other sources of Darkvision

•  Darkvision: A spell which grants regular Darkvision of 12 m (40 ft) until the next Long Rest.
•  Elixir of Darkvision: A potion which grants regular Darkvision of 12 m (40 ft) until the next Long Rest.
•  Steelwatcher Helmet: Grants the passive Artificial Sight which is equivalent to regular Darkvision.
•  Sunwalker's Gift: Grants the passive Sunwalker's Gift which is equivalent to regular Darkvision, but does not set ActiveCharacterLight (see above).
•  Sarevok's Horned Helmet: Grants the passive Deathbringer's Sight which functionally provides Darkvision up to 5 m (17 ft).
•  Assassin of Bhaal Cowl: Grants the passive Murderous Sight which functionally provides Darkvision up to 5 m (17 ft).
•  Devil's Sight: An even better version of Superior Darkvision. It grants a Warlock with vision up to 24 m (80 ft) in both natural and magical darkness.

Bugs

• The Duergar sub-race gains  Darkvision from their Dwarf base race while also having  Superior Darkvision as a sub-race bonus. This causes their ActiveCharacterLight (see above) to be only 12 m (40 ft) even though their effective Darkvision range for the purpose of combat mechanics is 24 m (80 ft) as per DarkvisionRangeMin.
• The in-game description of Sarevok's Horned Helmet claims that it can boost the range of an existing source of Darkvision from 12 m (40 ft) to 15 m (50 ft), but this does not work.