There are three types of enmity generation: Damage, Healing, and Action.
Damage Enmity is enmity stemming from damage dealt to the enemy. Despite dealing no damage, Flash uses this formula (1200 potency). The multiplier for actions that say, “Increased Enmity” can be found in the “Increased Enmity” tab of the FFXIV - Tables spreadsheet (See Resources).
Healing Enmity is enmity generated by directly healing yourself or another player. This is important when examining the difference between an action like Elusive Jump and Lucid Dreaming. The former will simply cut your threat in half. The latter will cut your threat in half and then add enmity from gaining a buff.
Action enmity is enmity generated by performing a buff or debuff that does not deal damage or directly heal a player. ∑ Status Effect M is the sum of all status effect multipliers involved. If ( 1 + ∑ Status Effect M) is negative, your actions will only generate 1 point of enmity.
Damage Threat = ⌊ Damage × Increased Enmity ⌋ × ( 1 + ∑ Status Effect M ) ⌋
If the skill does not say “Increased Enmity” replace that variable with (1).
Spell Threat = ⌊ HP Restored / 2 ⌋ × ( 1 + ∑ Status Effect M ) ⌋ / # Aggroed Enemies ⌋
Abilities Threat = ⌊ HP Restored × 3 / 5 ⌋ × ( 1 + ∑ Status Effect M ) ⌋ / # Aggroed Enemies ⌋
This specifically refers to skills, such as Equilibrium and Second Wind, whose primary action is healing. It does not include indirect healing through Bloodbath or Synastry.
Buffs and Debuffs
Action Threat = ⌊ Level Lv, THREAT ⌋ × ( 1 + ∑ Status Effect M ) ⌋ / # Aggroed Enemies ⌋