Attack damage

Attack damage (or AD) directly increases the physical damage of a unit's autoattack and also improves the damage some champion abilities do. Every champion starts with some base attack damage that increases each level. Additionally, several items and champion abilities, as well as spells, buffs, runes and masteries grant bonus attack damage. The champion's total attack damage is the base attack damage plus the bonus attack damage. This statistic stacks additively in most circumstances. When there are percentual attack damage bonuses, they are first added together if there are several sources and then they multiply the total attack damage of the champion.

At level 18, base attack damage ranges from  to  ( and ).

Champion abilities
Note: Only the attack damage bonus effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.
 * increases his attack damage by 60 / 75 / 90 for 7 seconds.
 * increases his attack damage by 40 / 55 / 70 / 85 / 100 + 0.4 / 0.55 / 0.7 / 0.85 / 1 per 1% health he is missing for 5 seconds.
 * increases her attack damage by 15 / 20 / 25 / 30 / 35.
 * passively increases his attack damage by 8 / 10 / 12 / 14 / 16. He can also activate this ability to increase his attack damage for 7 seconds by 12 / 19 / 26 / 33 / 40 instead, also increasing nearby allied champions' attack damage by half of that amount for the duration.
 * increases his attack damage by 30 / 40 / 50 / 60 / 70 for 20 seconds.
 * passive gains attack damage equal to 10 / 12.5 / 15 / 17.5 / 20 / 22.5 / 25% of his bonus movement speed.
 * increases an allied unit's attack damage by 14 / 23 / 32 / 41 / 50 for 5 seconds.
 * increases his attack damage by 20 / 25 / 30 / 35 / 40% for 6 seconds.
 * passively increases his attack damage by 15 / 20 / 25 / 30 / 35 when the ability is not on cooldown and grants double that bonus for 10 seconds on activation. It is possible to have both bonuses activated if the cooldown gets refreshed during those 10 seconds
 * grants him 6.375% of the damage it deals as attack damage.
 * grants him 15 / 25 / 35 / 45 / 55 attack damage as long as he is on the trail created by the ability.
 * increases his attack damage by 7 / 14 / 21 / 28 / 35 + 1% of his max health for 6 seconds.
 * increases her attack damage by 1.5 / 2 / 2.5 / 3 / 3.5 when she is hit by an attack or hits an enemy. This buff lasts for 5 seconds and stacks up to 10 times. She can activate this ability to gain max stacks.
 * passively increases his attack damage by 25% of his armor.
 * increases her attack damage by 20% for 15 seconds.
 * increases his attack damage by 25 / 35 / 45 / 55 / 65 for as long as the ability is toggled on.
 * increases the attack damage of nearby allied champions by 4 / 8 / 12/ 16 / 20 while active and persists for two seconds after deactivation.
 * increases his attack damage by 30 / 50 / 70 and half of that to nearby allied champions for 10 seconds.
 * increases his attack damage by 20 / 25 / 30 / 35 / 40 for 8 seconds.
 * passively increases his attack damage by 5 / 10 / 15 / 20 / 25 + 0.15 / 0.20 / 0.25 / 0.30 / 0.35 per 1% of his health missing.
 * increases his attack damage by 20 / 28 / 36 for 7 seconds.
 * increases his attack damage by 8 / 12 / 16 / 20 / 24 while active.
 * increases her attack damage by 25 / 40 / 55 for 10 seconds.

Masteries

 * increases your champion's attack damage by 1 / 2 / 3.
 * increases your champion's attack damage by .125 / .25 / .375 / .5 per level.

Runes

 * and runes increase attack damage.

Neutral buffs

 * The buff grants 40 bonus attack damage for 4 minutes.

Champion's abilities
Note: Only the attack damage reduction effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them. Effects that reduces damage is not the same as decreasing a champion's attack damage.


 * decreases surrounding enemy champions' attack damage by 20 / 35 / 50 / 65 / 80 for 4 seconds.
 * reduces the opponent's attack damage by 10 / 12.5 / 15 / 17.5 / 20 for 8 seconds.

Neutral Debuff

 * Voracious Corrosion reduces a champion's attack damage by 50%.

List of champions' attack damage
increases his attack damage by 25% of his armor. This includes his base armor and is an innate passive ability thus essentially increasing his base damage unlike all other ranked champion abilities which are temporary or situational boosts to damage. The increase to his damage is at level 1 for a total of  and  at level 18 for a total of.

,, and are abilities that passively increases their respective champions' attack damage. They are ranked abilities and thus cannot be counted on for a bonus at level 1. However, arguments could be made that at level 18 they will have 5 ranks and thus this will increase their damage permanently.
 * raises 's total attack damage to.
 * raises 's total attack damage to a minimum of.
 * raises 's total attack damage to.

Trivia
AD can become negative. Auto attacks will deal no damage in this case.

The maximum attack damage attainable from Attack Damage equipment and buffs:
 * Summoner's Rift
 * 500 = 5 x
 * 110 =
 * 10 =
 * 40 =
 * Total Attack Damage = 660
 * Dominion
 * 95 =
 * 400 = 5 x
 * Total Attack Damage = 495
 * Twisted Treeline
 * 500 = 5 x
 * 110 =
 * 10 =
 * Total Attack Damage = 620

The optimum attack damage from runes and masteries:
 * 3 =
 * 21.87 = Greater Marks of Might
 * 9.81 = Greater Seals of Might
 * 6.57 = Greater Glyphs of Might
 * 13.5 = Greater Quintessence of Might
 * Total Attack Damage = 54.75

The optimum attack damage attainable from allies, not including the listed champions:
 * 16 =
 * 50 =
 * 20 =
 * 35 =
 * 8 =
 * Total Attack Damage: 133

With 5 x, grants 95 attack damage. Combined with, Olaf can achieve 194 attack damage. Combined with can achieve the highest potential attack damage in the game.

can achieve the highest possible attack damage in the game:
 * 116.3 = Base AD at level 18
 * 300 =
 * 133 = Allied Gangplank, Janna, Sona and Taric with Aegis of the Legion
 * 54.75 from Runes and Masteries.
 * Total Attack Damage = 604
 * Summoner's Rift Build = 1265
 * 4 x is arguably more efficient due to 100% critical strike chance, and 50% increased critical damage. His attack damage would only be 1185 AD (which is still the highest), but he'd be dealing a whopping 2,713 per attack to non-structures (or 2,821 with the crit damage mastery!).
 * Dominion Build = 1100
 * Twisted Treeline = 1185
 * 93 from Janna and Taric and Aeigs of the Legion.

has holds a more "sustainable" second place with:
 * 111 = Base AD at level 18
 * 105 = (combined active and passive, achievable upon scoring a kill with .)
 * 133 = Allied Gangplank, Janna, Sona and Taric with Aegis of the Legion
 * 54.75 from Runes and Masteries.
 * Total Attack Damage = 403.75
 * Summoner's Rift Build = 1064
 * 4 x is arguably more efficient due to 100% critical strike chance, and 50% increased critical damage. His attack damage would only be 984 AD, but he'd be dealing 2,460 per attack to non-structures (or 2,558 with the crit damage mastery).
 * Dominion Build = 899
 * Twisted Treeline Build = 984
 * 93 from Janna and Taric and Aeigs of the Legion.

SivHD surpasses both using, see: here. He achieves 1577 AD and 4153 movement speed. However, it is not currently known how this was possible given known rules regarding movement speed. Using the given information, only the following was calculated:
 * 340 = 4 x
 * SivHD claims that due to Bloodthirsters losing stacks, would be more efficient. This is incorrect. A Bloodthirster only loses half its stacks on death, reducing from full stacks down to 80. Gaining 5 kills post-death would increase this back up to 85.
 * 110 =
 * 10 = (not used by SivHD)
 * 8 = (allied)
 * 107 = Base Attack Damage
 * Total Attack Damage = 575
 * Due to use of Revive, use of is not possible and obtaining  or  would not be feasible.
 * 320 = Base Movement Speed
 * 130 =
 * 75% =
 * 50% =
 * 40% = (Mantra)
 * 55% =
 * 52% =
 * 3% =
 * 2% =
 * 125% = with
 * 35% = with
 * 40% = (allied)
 * 15% =
 * Total Percentile Bonus = 492%
 * Raw Movement Speed = 2420
 * Actual Movement Speed = 1440 (1120 bonus)
 * Bonus AD from = 280
 * Total Attack Damage using this build = 855
 * Calculated damage using SivHD's build = 825 (much less than 1577 as shown).
 * Note SivHD's build has higher on-hit damage due to 100% Critical Strike Chance from 4 x, although the given AD is lower.

For the SivHD's video to be possible, one or more of the given movement speed bonuses are stacking multiplicatively rather than additively.