Strength is a rough measurement of the fighting prowess of a unit in Civilization VI. There are five different types of Strength, which can be modified by factors such as Policy Cards, promotions, and terrain:
- Combat Strength determines how much damage a unit inflicts in melee combat and how much damage it sustains when defending against attacks of any sort (in which case it can be called "Defense Strength"). Attacks that use Combat Strength inflict greatly reduced damage against city and district defenses, but are also the only kinds of attacks that can capture cities. Notably, the terms "Strength" and "Combat Strength" are sometimes used interchangeably.
- Ranged Strength is unique to ranged, naval ranged, and air fighter units. It determines how much damage a unit inflicts with ranged attacks. Attacks that use Ranged Strength inflict half damage against city and district defenses.
- Bombard Strength is unique to siege and air bomber units. It determines how much damage a unit inflicts with siege-type ranged attacks. Attacks that use Bombard Strength inflict full damage against city and district defenses and reduced damage against other units.
- Anti-Air Strength is unique to late-game naval units, certain support units, and Giant Death Robots. It determines how much damage a unit inflicts against attacking air units. Note that only units possessing this feature can retaliate against air attacks!
- Religious Strength is unique to religious units. It determines how much damage a unit inflicts and sustains when fighting other religious units, as well as its efficiency when converting cities to its religion.
Strength should not be confused with Hit Points (HP), which determine how much damage a unit can sustain before dying.