Distance

Distance in Path of Exile is measured in unnamed length units. These units are tied to the game's isometric perspective and viewing angle, and are not analogous to feet or meters.

A measure of distance is sometimes given in skill descriptions. For example, such as Elemental Proliferation SupportElemental Proliferation SupportCold, Fire, Lightning, Support, AoE
Icon: S
Level: (1-20)
Cost & Reservation Multiplier: 110%Supports any skill that hits enemies, or could otherwise apply elemental ailments.(0-19)% increased Duration of Elemental Ailments on Enemies
Elemental Ailments inflicted by Supported Skills spread to other enemies within (1.2-1.5) metres
Supported Skills have 20% chance to Freeze, Shock and Ignite

Additional Effects From 1-20% Quality:
(0.5-10)% increased Duration of Elemental Ailments on EnemiesThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Skill Gem you wish to augment. Right click to remove from a socket. lists the radius of its area of effect as a number of units.

For information about radius of skills and attack range see area of effect and range.

"Nearby"

The word "nearby" is used in the descriptions of many skill effects, passive bonuses and item modifiers. "Nearby" is not a keyword; it merely indicates that an effect applies in a circular area centered on the character. In descriptions where "nearby" is used, the actual radius of the area of effect is not given, and it may range widely from barely outside of melee range to covering most of the screen. This is a common source of confusion for players who assume that "nearby" is a keyword that means a specific number of units, similar to how the keyword "recently" always means "within the last four seconds".

Collation of known distances

Unit Distance / Radius Visualized.

Transparent unit visualizer, for 1920x1080.

1 unit	Hideout decorations can be moved in increments of one unit.
2 units	Radius (hitboxes) of Humanoids (such as player-controlled characters).
4 units	Default knockback distance.
4 to 7 units	Range of melee attacks.
10 units	Projectiles up to this distance get the full 30% more damage from Point Blank.
12 units	The tiles in Enlightened Hideout are 12 units wide.
18 units	Near 0% more damage from Far Shot at this range.
22 units	Minion Instability explosion radius.
25 units	The definition of "nearby" on unique item Belt of the DeceiverBelt of the Deceiver Heavy BeltRequires Level 20+(25-35) to Strength(15-25)% increased Global Physical Damage You take 30% reduced Extra Damage from Critical Strikes +(30-40) to maximum Life +(10-15)% to all Elemental Resistances Nearby Enemies are IntimidatedIn battle, virtue matters not. Only victory..
28 units	The definition of "nearby" for Flesh and Stone and Blood and Sand auras.
30 units	The definition of "nearby" for the Chilling Presence notable.
35 units	0% more damage from Point Blank at this range. The definition of "nearby" on Redeemer-influenced body armour mod "Nearby Enemies are Blinded" The definition of "nearby" on unique item SingularitySingularity Platinum SceptreSceptre Physical Damage: 51-76 Critical Strike Chance: 6.00% Attacks per Second: 1.25 Weapon Range: 1.1 metresRequires Level 62, 113 Str, 113 Int30% increased Elemental DamageAdds (1-10) to (150-200) Lightning Damage to Spells (14-18)% increased Cast Speed (6-8)% reduced Mana Cost of Skills Nearby Enemies are Hindered, with 25% reduced Movement Speed 100% increased Damage with Hits and Ailments against Hindered EnemiesIn time, all becomes nothing. We just expedite the process.. The definition of "nearby" on unique item Bear's GirdleBear's Girdle Leather BeltRequires Level 68+(25-40) to maximum LifeAdds (5-7) to (11-12) Physical Damage to Attacks (20-30)% increased Stun Duration on Enemies Nearby Enemies are Crushed while you have at least 25 Rage (4-6)% increased Physical Damage per 10 Rage +20 to Maximum RageSimple. Deadly. Unstoppable. The definition of "nearby" on Occupying Force.
40 units	The definition of "nearby" on unique item Victario's CharityVictario's Charity Laminated Kite ShieldChance to Block: 24% Armour: (113-133) Energy Shield: (23-27) Movement Speed: -3%Requires Level 50, 65 Str, 65 Int+8% to all Elemental Resistances+(50-70) to maximum Life +(20-30)% to Lightning Resistance +11% to Chaos Resistance 20% increased Area of Effect of Aura Skills 10% chance to grant a Power Charge to nearby Allies on Kill 5% chance to grant a Frenzy Charge to nearby Allies on HitA man's life is the greatest gift he can give. and previously for Ascendancy notables.
46 units	The definition of "nearby" for War Banner and Dread Banner auras.
50 units	The aura radius on unique item Victario's FlightVictario's Flight Goathide BootsEvasion: (84-135)Requires Level 12, 26 Dex+15 to Dexterity +15 to Intelligence (100-150)% increased Evasion Rating (10-20)% increased Movement Speed (10-20)% increased Movement Speed when on Low Life Quicksilver Flasks you Use also apply to nearby AlliesAlive but not unscathed, Victario fled as slaughter blossomed at the gates. and definition of "nearby" on unique item Perquil's ToePerquil's Toe Gold AmuletRequires Level 29(12-20)% increased Rarity of Items found+(40-50) to Dexterity (5-8)% increased Movement Speed Lightning Damage of Enemies Hitting you is Lucky Nearby Allies' Damage with Hits is LuckyHe was a lot luckier before he lost this..
60 units	The definition of "nearby" on Ascendancy notables other than Occupying Force, and Fossil-crafted Delve League helmet suffixes.
70 units	The definition of the "nearby" in "while a Rare or Unique enemy is nearby" crafted modifiers. Projectiles at and beyond this distance get the full 60% more damage from Far Shot.
75 units	The definition of "nearby" on unique items Leer CastLeer Cast Festival MaskEvasion: (77-88) Energy Shield: (17-19)Requires Level 28, 33 Dex, 33 Int+(20-30) to Dexterity 25% reduced Damage +(60-100) to maximum Life +(60-100) to maximum Mana You and nearby allies gain 50% increased DamageFor none of us are as cruel as all of us. and Dying BreathDying Breath Iron StaffWarstaff Physical Damage: 14-42 Critical Strike Chance: 6.40% Attacks per Second: 1.30 Weapon Range: 1.3 metresRequires Level 13, 27 Str, 27 Int+18% Chance to Block Attack Damage while wielding a Staff18% increased Cast Speed 18% increased maximum Mana 18% increased Area of Effect of Aura Skills 18% increased Area of Effect of Hex Skills Nearby Enemies have 18% increased Effect of Curses on them Nearby allies gain 18% increased Damage 18% increased effect of Non-Curse Auras from your SkillsThe whispers of the dead Carry wisdom for the living, If you are willing to give your life To listen..
85 units	Approximate horizontal distance from your character to the edge of the screen on a 1920 pixel wide resolution.
120 units	The definition of "nearby" on passive keystone Conduit.
150 units	Maximum distance a projectile can travel. −30% damage from Point Blank at maximum range.