The Darkness spell in 5e: how it works on a grid, who can see, and who gets advantage

How big is a 15-foot sphere of Darkness on a grid?

Put the point of origin on a grid intersection. A 15-foot radius runs 3 squares out in each direction, so the sphere sits inside a 6 by 6 block, 30 feet across. Count the squares whose centres fall inside the circle and you get 32: the whole block minus its four corner squares. Some tables use the full 36 for speed, which is a table ruling and a fair one.

It is a sphere, so it also rises 15 feet above the point. A creature flying 20 feet over the middle is outside it, and a balcony 10 feet up sits inside. On a flat map, say where the top is before someone climbs.

Who is Blinded, and what happens to attacks?

Darkness makes the area heavily obscured, and you have the Blinded condition while trying to see something in a heavily obscured space. That produces four situations worth writing on a card:

• Attacker outside, target inside: the attacker cannot see the target, so disadvantage.
• Attacker inside, target outside in light: the target cannot see the attacker, so advantage.
• Both inside: each is unseen by the other, advantage and disadvantage cancel, roll normally.
• Spells that need a creature you can see cannot target anyone inside, even when range and path are clear.
• Anyone inside can take the Hide action, because the area is heavily obscured.

Does the Blind Fighting style work in Darkness?

Yes, within 10 feet. In the 2024 rules Blind Fighting is a Fighting Style feat that gives Blindsight with a range of 10 feet. Fighters, paladins and rangers can take it through their Fighting Style feature.

On a grid that is 2 squares in every direction. A fighter inside the sphere sees every creature within 2 squares and attacks them normally, while those creatures cannot see the fighter and attack at disadvantage. Beyond 2 squares the fighter is as blind as anyone. Blind Fighting pairs well with an ally who casts Darkness on the fighter's square, because the enemies who close in lose the fight for sight while the fighter keeps it.

Casting it on an object, and moving the darkness

The 2024 spell can also be cast on an object that is not being worn or carried. The darkness then fills a 15-foot emanation from the object, which moves with it. Covering the object with something opaque, such as a bowl or a helm, blocks the darkness. The 2014 version also let you cast it on an object you were holding, which the 2024 wording no longer allows.

The spell does not say what happens once someone picks the object up, so a common table ruling is that the emanation keeps going and moves with it. A pebble thrown 30 feet moves the whole blind zone 6 squares. Darkness also dispels any overlapping bright or dim light made by a spell of level 2 or lower, such as Light.