- Not available on that edition (the reason is in the tooltip)
- Depends on the setting, your class or another addon (details in the tooltip)
What it does
Checks how much health the unit specified has as a percentage of its maximum health, compared with the percentage you set.
Why you might use it
Compare a unit's health as a percentage of its maximum. This is the usual way to gate execute abilities, such as Execute or Hammer of Wrath only below 20% health, or Drain Soul as a target nears death, and to bring up a defensive such as Shield Wall or a Healthstone when your own health drops under 30%. Not available on Retail or Forever, where the game hides health values from addons. See also Health, Time Until Health Percentage and Health Percentage Within Range.
Example
your target's health is less than 20%
Settings
What each setting in the condition editor means, from the game's own help.
Unit - The unit this condition uses as the target of comparison.
Operator - How to compare Health Percentage with the Health value. This comparison uses basic mathematical comparison operations.
Health - The health value of Unit as a percentage of their total health.