Dexterity

Dexterity is an Ability Score and a key ability of Rogues, Rangers, Monks, and other wielders of weapon with Finesse property.

Dexterity affects your Acrobatics, Sleight of Hand, and Stealth skills, as well as your attack rolls for ranged weapons and Finesse weapons. It also affects your Initiative and Armour Class.

Dexterity Checks

A Dexterity check can model any attempt to move nimbly, quickly, or quietly, or to keep from falling on tricky footing. The Acrobatics, Sleight of Hand, and Stealth skills reflect aptitude in certain kinds of Dexterity checks.

Acrobatics

Your Dexterity (Acrobatics) check covers your attempt to stay on your feet in a tricky situation, such as when you're trying to run across a sheet of ice, balance on a tightrope, or stay upright on a rocking ship's deck. The DM might also call for a Dexterity (Acrobatics) check to see if you can perform acrobatic stunts, including dives, rolls, somersaults, and flips.

Sleight of Hand

Whenever you attempt an act of legerdemain or manual trickery, such as planting something on someone else or concealing an object on your person, make a Dexterity (Sleight of Hand) check. The DM might also call for a Dexterity (Sleight of Hand) check to determine whether you can lift a coin purse off another person or slip something out of another person's pocket.

Stealth

Make a Dexterity (Stealth) check when you attempt to conceal yourself from enemies, slink past guards, slip away without being noticed, or sneak up on someone without being seen or heard.

Uses of Dexterity

Attack rolls and Damage

Creatures add their Dexterity modifier to the results of attack and damage rolls of ranged weapons and, and the creature's can choose between their Dexterity score or Strength score for melee weapons with the Finesse property.

Armour Class

Creatures also add their Dexterity modifier to their Armour Class (AC) - making them more difficult to hit, up to a maximum of +2 when wearing most medium armour. The bonus is ignored when wearing heavy armour, unless otherwise specified.

Initiative determines the order of turns during combat. Initiative is a Dexterity ability check.

Sometimes a DM might have combatants use their Initiative scores instead of rolling Initiative. Your Initiative score equals 10 plus your Dexterity modifier. If you have Advantage on Initiative rolls, increase your Initiative score by 5. If you have Disadvantage on those rolls, decrease that score by 5.

Hide acttion

With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you're Heavily Obscured or behind Three-Quarters Cover or Total Cover, and you must be out of any enemy's line of sight; if you can see a creature, you can discern whether it can see you.

On a successful check, you have the Invisible condition. Make note of your check's total, which is the DC for a creature to find you with a Wisdom (Perception) check.

The condition ends on you immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component.

Passive Perception

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, which equals 10 + the creature's Wisdom modifier, as well as any other bonuses or penalties. If the creature has advantage, add 5. For disadvantage, subtract 5.

For example, if a 1st-level character (with a Proficiency Bonus of +2) has a Wisdom of 15 (a +2 modifier) and a Proficiency in Perception, he or she has a passive Wisdom (Perception) of 14.