What Is Ability Power and How Does AP Work in LoL?

If you have ever wondered why your Veigar one-shots an ADC or the damage your Lux deals increases every time you buy a shop-recommended item, ability power is the metric behind it.

In League of Legends, ability power (AP) is one of the two main offensive stats and the direct counterpart to attack damage (AD). Ability power scales up the damage (including magic damage) or utility (like heals and shields) of your champion's spells.

Every champion in the game begins with 0 ability power, and that number never grows through levels by default. The only way to increase ability power is through items, runes, buffs, and a handful of champion passives.

It stacks additively; one point of AP grants one flat point to the stat. Riot Games values it at roughly 20 gold per AP when balancing item prices, which is why higher-cost AP items tend to offer extra utility.

Unlike attack damage, ability power has no baseline effect on your basic attacks against champions or minions.

An AD champion with 100 attack damage hits harder with every auto attack the second the stat goes up. A champion with 100 AP does nothing extra with those autos until they either press a spell or build an on-hit item that converts AP into attack damage, such as Nashor's Tooth or Lich Bane.

The one exception is structures: basic attacks against turrets deal your base AD plus the higher of your bonus AD or 60 percent of your AP as magic damage, which is why a fed AP champ can melt a tower with auto attacks too.

Ability power is a flat number on your champion panel. And what matters is how your champion's QWER abilities scale off of ability power through ratios written into each tooltip. An ability with a 50 percent AP ratio gains 50 percent of your total AP as bonus magic damage. Build 400 AP, and that spell adds an extra 200 damage on top of its base damage before any further multipliers apply.

Those ratios are not limited to damage output either. Ability power also most commonly scales the potency of secondary effects on many abilities. Shield strength, healing numbers, slow duration, cast range, and even movement speed buffs scale off of ability power on plenty of champions. Morgana's Black Shield, Lulu's Whimsy, Soraka's healing, and Nami's bounces on Ebb and Flow all get stronger as the enchanter's gold turns into ability power.

Items are the primary source of AP for every champion in League of Legends. Some grant flat AP, some grant AP plus utility like mana or ability haste, and one item, in particular, straight-up multiplies the AP you already own.

Rabadon's Deathcap is one of the strongest and most expensive AP items. For 3,500 gold, it grants 130 AP plus a unique passive that adds another 30 percent to your total AP. Buy it after a couple of other AP items, and the compound scaling makes spells genuinely terrifying. Void Staff cuts through stacked magic resistance on tank comps. Shadowflame punches squishier targets even harder once their health drops below a threshold. And Season 2026's item overhaul brought in brand-new arrivals like Actualizer for heavy-mana mages like Ryze and Dusk and Dawn for AP fighters like Gwen and Diana.

Adaptive Force rune shards grant a small flat AP bonus right out of the fountain, letting mages start the laning phase with extra pop. Gathering Storm ramps AP up the longer the game drags on, which is why scaling mages love it. Absolute Focus grants bonus AP while you stay above 70 percent health, rewarding players who trade smart.

Map objectives like Dragon souls and neutral buffs matter too. A mage stacking kills through the mid-game also snowballs their AP faster because item components become affordable earlier, and that snowball is where lanes actually break open.

Veigar is an outlier worth noting: his Phenomenal Evil Power passive grants 1 ability power for every ability he lands on a champion, plus 5 per takedown, meaning he is the single carry who can infinitely increase his ability power from pure gameplay alone. Thresh can also infinitely stack AP by passively absorbing the souls of dead enemies, but he’s a support tank.

AP damage is magic damage, so magic resistance (MR) reduces it the same way armor reduces physical damage.

A target takes magic damage divided by (1 + MR/100): 100 MR cuts your damage in half; 200 MR cuts it by about two-thirds. Every point of MR adds 1 percent effective health against your spells, with no diminishing returns, so letting the enemy freely stack MR quietly kills your output.

Most champions start at around 30 base MR before buying anything, which is why your level 1 poke lands for less than the tooltip number.

The counter to MR is magic penetration (MPen), which comes in two types.

Flat magic penetration subtracts a fixed amount from the target's MR for your damage only: Sorcerer's Shoes and Shadowflame provide it, and it does the most against low-MR squishies.

Percentage magic penetration multiplies the target's MR down: Void Staff ignores 40 percent, Cryptbloom 30 percent, and scales better the more MR the enemy stacks.

If you carry both types, percentage penetration applies first, then flat, which is how mages punch through even a solid MR stacker. Neither MPen type changes the enemy's real MR stat, only the value your spells calculate against, and neither can push a target below 0 MR. 

The practical rule: the answer to a tanky enemy is rarely more raw AP. Against a squishy team with no MR, flat pen from Sorcerer's Shoes and Shadowflame beats other items per gold; against a comp stacking magic resist, Void Staff's percentage shred is mandatory, because 40 percent off a 200-MR tank strips more effective resistance than any flat item can. Reading which to buy and when to pivot is where most hardstuck mages leak damage without noticing. And it's the fastest thing a pro League of Legends coach can fix: catching a bad pen build in one game and handing you the correct playbook you wouldn’t get over a season.

Twenty-three champions in the current League of Legends roster have exactly zero AP ratios anywhere in their kit. Building ability power on any of them is meaningless and is trolling teammates.

The full list: Aatrox, Ambessa, Camille, Darius, Dr. Mundo, Draven, Garen, K'Sante, Kayn, Kled, Naafiri, Nilah, Olaf, Pyke, Riven, Samira, Sett, Talon, Urgot, Xayah, Yone, Zaahen, and Zed.

Most of these are juggernauts, skirmishers, and assassins whose kits were designed around base stats, health, attack damage, or resource-free rage mechanics.