Magic resistance (MR) is a stat that reduces incoming magic damage by a percentage. 100 MR cuts magic damage in half. 200 MR reduces it by 66.6%. Every point of MR increases your effective health against magic damage by 1%, with no diminishing returns. When the enemy team has two or more AP threats, one MR item can swing fights that are otherwise losing. The counter to MR is magic penetration. Item picks and strategy for AP players below.
How Magic Resist Works
The damage formula is: post-mitigation damage = raw magic damage ÷ (1 + MR ÷ 100).
At 100 MR, an ability dealing 1,000 raw damage hits for 500. At 200 MR, that same ability hits for 333. The percentage reduction formula is MR ÷ (100 + MR). At 100 MR that is 100 ÷ 200 = 50%. At 200 MR it is 200 ÷ 300 = 66.6%.
MR stacks additively. A 50 MR item and a 55 MR item together give 105 MR with no interaction penalty. There are no diminishing returns. Each additional point of MR adds 1% more to your effective health pool against magic damage regardless of how much you already have. 300 MR is four times as effective as 30 MR, not three times.
Magic penetration reduces the effective MR the attacker uses in their damage calculation, not your actual stat. Void Staff's 40% magic pen means the attacker treats your 100 MR as 60 MR. Your item stats, rune bonuses, and any other effects relying on your MR still see the full value.
MR vs. Magic Damage: Damage Table
The table below shows what percentage of magic damage gets through at each MR level. Lower percentages mean less damage received.
| Enemy MR | No Magic Pen | 40% Magic Pen (Void Staff) |
|---|---|---|
| 0 | 100.0% | 100.0% |
| 30 | 76.9% | 84.7% |
| 50 | 66.7% | 76.9% |
| 100 | 50.0% | 62.5% |
| 150 | 40.0% | 52.6% |
| 200 | 33.3% | 45.5% |
| 250 | 28.6% | 40.0% |
| 300 | 25.0% | 35.7% |
At 100 MR you absorb 50% of all incoming magic damage. That is roughly what you reach after one core MR item plus your champion's base MR (usually 30–40). Void Staff closes the gap: at 100 MR you take 62.5% instead of 50%. Against a mage who already has Void Staff, stacking to 150–200 MR is the correct counterplay before they can add a second penetration item.
At 200 MR, even Void Staff only gets through 45.5% of the mage's raw damage. At that point most AP carries pivot to targeting your lower-MR teammates rather than trying to burn through your resistance.
Magic Resist vs. Health
Health and MR both increase effective health against magic damage, but in different ways. Health is universal: it increases your buffer against physical damage, true damage, and magic damage equally. MR only helps against magic sources.
The efficiency crossover is around 100 MR. Below 100 MR, adding HP generally gives more total effective health per gold than adding more MR. Above 100 MR, each point of MR outpaces an equivalent HP investment for magic-specific effective health. That is why most tanks target 120–150 total MR against a double-AP comp rather than stacking pure HP, but rarely build three or four pure MR items unless the entire enemy team deals magic damage.
Most MR items include HP for this reason. Kaenic Rookern (400 HP + 80 MR), Spirit Visage (400 HP + 50 MR), and Force of Nature (400 HP + 55 MR) all give meaningful HP alongside MR. Banshee's Veil is the major exception: it skips HP entirely in favor of AP, which is why it is an AP mid buy rather than a tank buy.
All Magic Resist Items (2026)
| Item | Gold | MR | HP | Other Stats | Role |
|---|---|---|---|---|---|
| Kaenic Rookern | 2,900 | 80 | 400 | 100 Percent Base Health Regen | Tank / Support |
| Force of Nature | 2,800 | 55 | 400 | 4 Move Speed | Tank |
| Abyssal Mask | 2,850 | 50 | 350 | 15 Ability Haste | Tank / Support |
| Spirit Visage | 2,700 | 50 | 400 | 10 Ability Haste, 100 Percent Base Health Regen | Tank / Bruiser |
| Jak'Sho, The Protean | 3,200 | 45 | 350 | 45 Armor | Tank |
| Wit's End | 2,800 | 45 | - | 50 Attack Speed, 20 Percent Tenacity | Fighter / On-hit |
| Maw of Malmortius | 3,100 | 40 | - | 15 Ability Haste, 60 AD | AD Bruiser |
| Banshee's Veil | 3,000 | 40 | - | 105 AP | AP Mage |
| Hollow Radiance | 2,800 | 40 | 400 | 10 Ability Haste, 100 Percent Base Health Regen | Tank |
| Mercurial Scimitar | 3,200 | 35 | - | 50 AD, 10 Life Steal | ADC |
| Locket of the Iron Solari | 2,200 | 25 | 200 | 10 Ability Haste, 25 Armor | Support / Tank |
| Mercury's Treads | 1,250 | 20 | - | 45 Move Speed, 30 Percent Tenacity | All |
MR values from patch 16.9.1.
What distinguishes each item beyond its MR value:
- Kaenic Rookern — highest MR of any item; passive shield refreshes after 15s without taking magic damage
- Force of Nature — passive stacks to +70 bonus MR after 8 magic hits from champions; best vs. sustained AP poke
- Abyssal Mask — nearby enemies take 12% more magic damage; enables AP allies to deal through the MR
- Spirit Visage — amplifies all heals and shields by 25%; pairs with lifesteal, drain tanks, or healing supports
- Jak'Sho, The Protean — stacks bonus armor and MR mid-fight; best when facing both AD and AP damage
- Wit's End — attack speed + MR + tenacity; for melee fighters and on-hit champions facing AP threat
- Maw of Malmortius — Lifeline magic shield triggers below 30% HP; core AD bruiser buy vs. AP mid or jungle
- Banshee's Veil — spell shield blocks one enemy ability; standard AP mid buy against assassination or one-shot threats
- Hollow Radiance — Immolate deals AoE magic damage to nearby enemies; for tanks that also push damage
- Mercurial Scimitar — active removes all CC (QSS effect); AD + MR for ADCs vs. hard CC chains or AP burst
- Locket of the Iron Solari — active grants a brief shield to nearby allies; primarily support / engage tank
- Mercury's Treads — boots; also grants 30% tenacity to reduce stun, slow, and root durations
When to Build MR
Build MR when two or more enemy champions deal primary magic damage: a mage mid, AP jungle, or AP support, especially if one of them is a high-burst assassin like Syndra, LeBlanc, or Fizz. The practical trigger: if the enemy team has at least two AP-primary champions, buy your first MR item before or during your third item slot.
Role-based MR targets:
- Tank / engage support: Target 120–150 total MR against a heavy AP comp. Kaenic Rookern is the best first buy into AP-heavy matchups; the passive shield refreshes without cooldown during downtimes. Force of Nature is stronger into sustained poke (Lux, Xerath, Karma) because its passive stacks up during the laning phase. Spirit Visage is the right pick when you have a healer in your support slot or play a drain-tank champion (Vladimir, Warwick).
- Top or jungle bruiser: Maw of Malmortius is the standard first MR buy for AD bruisers against AP mid or jungle. The Lifeline shield routinely prevents one-shot death windows. Spirit Visage is better if you run any lifesteal or drain-tank ability. Wit's End is an alternative for melee on-hit or attack-speed fighters who also want the tenacity.
- ADC: Mercury's Treads when the enemy AP threat also has hard CC (stuns, suppresses). Mercurial Scimitar when facing a champion whose CC is a death sentence (Malzahar suppress, Mordekaiser ultimate) and the active cleanse is required. Otherwise, ADCs rarely invest beyond Mercury's Treads because their positioning and HP are better defenses than item MR.
- AP mid / mage: Banshee's Veil is the right MR buy in almost every case. The spell shield blocks a single ability entirely and often prevents the combo that would one-shot you. Buy it when an assassin jungler or opposing mid has a reliable kill window. Locket of the Iron Solari is a support and engage-tank item, not an AP mage item.
Do not build MR reactively against a full AD team. If no enemy champion has meaningful AP scaling past the 20% base magic damage from select on-hit effects, every gold spent on MR delays a damage or armor item. Check the enemy team composition before spending 2,700–3,200 gold on a defensive purchase.
How to Counter Magic Resist
MR stacking reduces flat AP damage. The direct answer is magic penetration. The strategic answer is targeting enemies who have not built MR yet.
Magic Penetration Items
- Void Staff (3,000g) — 40% magic penetration; mandatory vs. any enemy stacking MR past 100
- Cryptbloom (3,000g) — 30% magic pen + nova heal on kill; jungler and support AP option
- Shadowflame (3,200g) — 15 flat magic pen + 20% bonus damage below 40% HP; strong vs. targets with low MR or shields
- Sorcerer's Shoes (1,100g) — 12 flat magic pen; standard boots for AP champions in most matchups
Sorcerer's Shoes is the correct boot choice for almost every AP champion in matchups where dealing damage is a priority. At 12 flat magic pen, they cut a 30-MR support's effective MR to 18, a meaningful relative increase in your damage against soft targets. Buy them early and extract their value before enemies start stacking MR items.
Flat vs. Percent Magic Penetration
Flat penetration (Sorcerer's Shoes, Shadowflame) is most efficient against low-MR targets. 12 flat pen against a 30-MR support is a 29% relative damage increase. That same 12 flat pen against a 150-MR tank is only an 8% relative increase.
Percent penetration (Void Staff, Cryptbloom) scales with the target's MR. Void Staff's 40% removes 40 effective MR from a 100-MR target, 60 MR from a 150-MR target, and 80 MR from a 200-MR target. Against a tank who has spent three items building MR, Void Staff is required; nothing else closes the gap at that MR level.
In most AP games the efficient path is: Sorcerer's Shoes early, then Void Staff as a third or fourth item once enemies begin buying MR. If the enemy team has no dedicated MR stackers, skip Void Staff and take a second damage item instead.
Target Selection Over Resistance Stacking
The most efficient counter to a 200-MR tank is to stop targeting it. AP mages deal their highest damage-per-gold against targets at 30–60 MR: supports, ADCs, and other mages who have not itemized MR at all. If the enemy tank is specifically stacking MR to absorb your damage, force fights around objectives, let your AD carries handle the backline, and apply your magic damage to softer targets.
AP damage is most effective when it is falling on unprepared enemies, not on tanks built around absorbing it.
