Damage Types and Armor: what turns into what

Three damage types

In Dota all damage splits into three types, and each has its own defense. Understanding them is understanding why the same item saves you in one game and is useless in another.

• Physical. Almost all auto-attacks and some abilities. Reduced by armor and damage block.
• Magical. Most abilities. Reduced by magic resistance (base 25% on heroes).
• Pure. The most "honest" type: it ignores armor and resistance. Many dangerous ultimates deal it.

How armor works

Armor reduces only physical damage, and it works less linearly than it looks:

1. One point of armor ≈ +6% survivability. Against physical damage each point adds roughly 6% to your effective health — not to your raw HP, but to how much physical damage you can soak.
2. Percent return diminishes, EHP stays nearly linear. The percentage reduction grows slower and slower, but survivability climbs steadily, so armor is valuable at 5 points and at 30.
3. Negative armor amplifies damage. Armor-reduction effects (Desolator, Medusa, Slardar) push it into the negatives — and then physical damage on the target actually increases.
4. Armor sources stack. Base armor from agility plus items and auras all add into a single number, and resistance is computed from that.

That's why against a strong carry you build armor and damage block, not magic resist. For the items that provide it, see the guides on neutral items and starting items.

Magic and resistance

A separate stat works against magic damage — magic resistance:

• Base 25%. All heroes take 25% less magic damage by default — so 75% gets through.
• Stacks multiplicatively. Hood of Defiance, Pipe of Insight and Glimmer Cape add resistance on top of the base, not as a flat sum of percentages.
• Useless against physical. Magic resist does nothing if a carry is killing you with auto-attacks — there you need armor.
• Can be pierced. Some abilities and items lower the target's resistance, increasing incoming magic.

The main tool against magic burst is Black King Bar: it grants temporary immunity to most spells, not just resistance.

Pure damage and block

Pure damage is what neither armor nor magic resist saves you from:

• Bypasses defenses. Pure damage ignores both armor and magic resistance — which is why it's so popular on "kill" ultimates.
• Not stopped by shields. Damage block (Stout Shield, Vanguard, Crimson Guard) only cuts physical hits — it does nothing to magic or pure.
• Only immunity stops it. Going damage-immune helps, as do effects like Aeon Disk that trigger at a health threshold.
• BKB doesn't always help. Some pure damage goes through even spell immunity — read the specific ability's description.

Common mistakes

These defensive mistakes cost the most lives:

• Buying magic resist against a carry. Pipe won't stop auto-attacks — against physical you need armor and block.
• Stacking armor against a mage. Armor does nothing against ability burst; get BKB and magic resist.
• Trusting BKB against pure. Some pure damage goes through immunity — check the source.
• Ignoring negative armor. If the enemy has Desolator or an armor-reduction aura, your defense drops into the negatives and physical damage climbs.

FAQ