Range is a measurement used to determine how far an autoattack or ability can reach. It shares the scale with movement speed, so one point translates to one game distance unit traveled. Note that autoattack range is measured differently to ability range. Given a source unit's hitbox and a target unit's hitbox, range is calculated as follows: autoattack range from edge to edge; targeted skill range from center to center; skillshot range from edge to edge; and the range of self-centered area of effects are from the edge of the source (the larger champions don't benefit less from auras than smaller champions). The difference is approximately 100 (i.e. 550 autoattack range is roughly 650 casting range)[1][2][3]
Each champion begins the game with a particular base autoattack range. This can vary from 125 to 175 for melee units and 400 to 650 for ranged units. The highest base autoattack range for champions is held by 
Caitlyn.
At level 18, the highest autoattack range is 669 held by 
Tristana surpassing Caitlyn at level 16 with 650 autoattack range. This is because of Tristana's 
Draw a Bead.
Abilities
Attack Range Modifiers
The following abilities increase the champion's respective attack range, without affecting things such as 
Crest of Cinders, 
Frozen Mallet, 
Tiamat, 
Ravenous Hydra, and 
Runaan's Hurricane.
Aatrox's Massacre increases his attack range to 325 from 150 for 12 seconds.- Azir's Arise! replaces his basic attack with Sand Soldiers 375 attack range attack that can be used if Azir is in 800 units range from soldier
- Cho'Gath's Feast increases his attack range by 3.8 / 6.1 / 8.3 per stack. The maximum is +50 at rank 3 and 6 stacks.
- Ekko's Phase Dive increases his attack range to 600 after dashing, and causes him to blink to his target upon auto attack.
- Hecarim's Devastating Charge increases his attack range to 325 from 175 for the attack.
- Jinx's Fishbones increases her attack range to 600 / 625 / 650 / 675 / 700 from 525.
- Kassadin's Nether Blade increases his attack range to 200 from 150 for the attack.
- Kha'Zix's Taste Their Fear increases his range to 175 from 125 upon evolving the ability after leveling his ultimate, Void Assault.
- Kog'Maw's Bio-Arcane Barrage increases his attack range to 630 / 650 / 670 / 690 / 710 from 500 for 8 seconds.
- Leona's Shield of Daybreak increases her attack to 155 from 125 for the attack.
- Nasus' Fury of the Sands increases his attack range to 175 from 125 for the duration.
- Nidalee's Takedown increases her attack range from 125 to 200 for the attack.
- Renekton's Ruthless Predator increases his attack range to 175 from 125 for the attack.
- Rengar's Unseen Predator increases his range to 600 (725 with 6 trophies on Bonetooth Necklace) from 125 while in brush and 0.5s after leaving brush, causing him to leap at his target.
- Riven's Blade of the Exile increases her attack range to 200 from 125 for 15 seconds.
- Sejuani's Flail of the Northern Winds increases her attack range to 175 from 125 for her next attack only. Her attack range is increased to 150 for the area of effect portion of the spell.
- Tristana's Draw a Bead increases her base attack range of 543 by 7 with each level (+ 126 at level 18).
- Twitch's Rat-Ta-Tat-Tat increases his attack range to 850 from 550 for 7 seconds.
- Wukong's Crushing Blow increases his attack range to 300 from 175 for the attack.
Range Type Modifiers
The following abilities change a champion attack classification from "Ranged" to "Melee", or vice versa. This affects things such as Crest of Cinders, Frozen Mallet, Tiamat, Ravenous Hydra, and Runaan's Hurricane.
- Elise's Spider Form decreases her attack range to 125 from 550 until she switches stances.
- Gnar's Rage Gene decreases his attack range to 150 from 400-485 until he switches stances.
- Jayce's Transform: Mercury Cannon increases his attack range to 500 from 125 until he switches stances.
- Kayle's Righteous Fury increases her attack range to 525 from 125 for 10 seconds.
- Nidalee's Aspect of the Cougar decreases her attack range to 125 from 525 until she switches stances.
- Quinn's Tag Team decreases her attack range to 125 from 525 for 20 seconds or until she uses Skystrike.
Chart
List of ranged champions from highest to lowest autoattack range.
| Champion | Range |
|---|---|
 Twitch (with  Rat-Ta-Tat-Tat)
|
850 |
 Kog'Maw (with rank 5 )
|
710 |
 Jinx (with rank 5  Switcheroo! while using Fishbones)
|
700 |
| Tristana (with Draw a Bead at level 18)
|
669 |
| Caitlyn
|
650 |
 Anivia,  Ashe
|
600 |
 Annie,  Varus,  Zyra
|
575 |
 Ahri,  Brand,  Cassiopeia,  Corki,  Draven,  Elise (with  Human Form),  Ezreal,  Heimerdinger,  Kalista,  Kennen,  Lissandra,  Lulu,  Lux,  Malzahar,  Miss Fortune,  Nami,  Ryze,  Sona,  Soraka,  Syndra, Tristana (with Draw a Bead at level 1), Twitch,  Vayne,  Ziggs,  Zilean
|
550 |
 Azir,  Graves, Jinx,  Karma,  Kayle (with  Righteous Fury),  LeBlanc,  Nidalee,  Orianna,  Quinn,  Twisted Fate,  Veigar,  Viktor,  Vel'Koz,  Xerath
|
525 |
 Bard,  Jayce (with  Transform: Mercury Cannon), Kog'Maw,  Lucian,  Sivir,  Swain,  Teemo
|
500 |
(with  Rage Gene at level 18)
|
485 |
 Fiddlesticks
|
480 |
 Janna
|
475 |
 Karthus,  Vladimir,  Morgana,  Thresh
|
450 |
 Urgot
|
425 |
| (with Rage Gene at level 1)
|
400 |
List of Melee champions.
Targeted Abilities (Exceptions)
The following targeted abilities calculate their range like a basic attack (edge-to-edge):
- Rappel
- Lucian's Piercing Light
- Miss Fortune's Double Up
- Tristana's Explosive Shot and Buster Shot
- Vayne's Condemn
- This list may be incomplete.
References
- ↑ Hitboxes, Range and Deflection. Retrieved 13 August 2012
- ↑ Annie q and normal attack same 625 range, but normal attack range longer than q, Why?. Retrieved 13 August 2012
- ↑ What's the difference between spell range and autoattack range?. Retrieved 13 August 2012