• Normal weapons are equally effective against all types of units.
• Concussion/Plasma weapons do 50% damage against Medium units and 25% against Large units.
• Explosive weapons do 50% damage against Small units and 75% against Medium units.

Some attacks, such as the Scarab explosion, also do "splash damage", which means that any units or buildings within a short radius of the attack point will take a peripheral amount of damage.

The following table lists each unit's size and damage type:

Terran Units
Unit	Size	Ground Attack	Air Attack
SCV	Small	Normal	-
Marine	Small	Normal	Normal
Firebat	Small	Concussive+	-
Ghost	Small	Concussive	Concussive
Vulture	Medium	Concussive	-
Siege Tank – Tank	Large	Explosive	-
Siege Tank – Siege	Large	Explosive*	-
Goliath	Large	Normal	Explosive
Wraith	Large	Normal	Explosive
Dropship	Large	-	-
Science Vessel	Large	-	-
Battlecruiser	Large	Normal	Normal
Medic	Small	-	-
Valkyrie	Large	-	Explosive+

Zerg Units
Unit	Size	Ground Attack	Air Attack
Larva	Small	-	-
Drone	Small	Normal	-
Zergling	Small	Normal	-
Hydralisk	Medium	Explosive	Explosive
Ultralisk	Large	Normal	-
Infested Terran	Small	Normal*	v-
Broodling	Small	Normal	-
Defiler	Medium	-	-
Queen	Medium	-	-
Overlord	Large	-	-
Scourge	Small	-	Normal
Mutalisk	Small	Normal	Normal
Guardian	Large	Normal	-
Lurker	Medium	Normal+	-
Devourer	Large	-	Explosive

Protoss Units
Unit	Size	Ground Attack	Air Attack
Probe	Small	Normal	-
Zealot	Small	Normal	-
Dragoon	Large	Explosive	Explosive
High Templar	Small	-	-
Archon	Large	Normal+	Normal+
Reaver	Large	Normal+	-
Shuttle	Large	-	-
Observer	Small	-	-
Scout	Large	Normal	Explosive
Carrier	Large	-	-
Interceptor	Small	Normal	Normal
Arbiter	Large	Explosive	Explosive
Dark Archon	Large	-	-
Dark Templar	Small	Normal	-
Corsair	Medium	-	Explosive+

* Weapon does splash damage to all units
+ Weapon does friendly splash damage (meaning it will hit allies and enemy units but not your own)