What's the difference between life, health, armour and shield?

Overwatch has many sources of health. What do all these terms mean?

• Health
• Life
• Armour
• Shield

Solution 1:

• Health or HP is your total life + shield + armour.
• Life is simply a number that represents how much damage you can take before you die.
• Armour reduces incoming damage.
• Shield self-regenerates over time.

Basically, armour and shield are similar to life, in that they contribute to your overall health, but they come with special attributes. A hero can have a mix of life, armour and shield that makes up their total health pool.

Shield will deplete before armour or life does, and armour will be damaged before life is.

Armour

Reduces incoming damage by 5 if the hit was 10 damage or more. If the damage is less than 10 then it is halved.

If a hero has innate armour, such as D.Va, then they will regain it through normal sources of healing (health packs, Mercy, etc). However, other sources of armour such as Torbjörn's armour pack are temporary bonuses and will be depleted from the hero once they run out and you will have to pick up another one.

For example:

1. Winston has 400 life and 100 armour for a total of 500 HP.
2. Soldier: 76 shoots a bullet that should deal 15 damage.
3. The bullet hits Winston but because he has armour it only deals 10 damage.
4. Winston has 400 life and 90 armour remaining.

Tracer shoots very quickly but each bullet doesn't hit hard. If her bullet does 4 damage, then armour will reduce it to 2 damage (halved).

Armour is more effective against smaller firearms such as Tracer and less effective against heavy-hitters such as Pharah and Junkrat.

Heroes such as D.Va have lots of innate armour (400 life and 200 armour).

Shield

Does not reduce incoming damage.

After three seconds of not taking damage, shield will regenerate at a rate of 25/sec.

Heroes such as Zenyatta have innate shield (50 life + 150 shield). Normal sources of healing will restore both the hero's life and shield.

Other abilities such as Zarya's Projected Barrier, Reinhardt's Shield or Winston's Barrier Projector are not shields in this sense. Instead, they are referred to as barriers and usually have their own health pool that is separate from the hero.

Solution 2:

Overshield / Overheal / Bonus Health

In addition to the above, the game also has an "Overshield" mechanic, only obtainable from Lucio's "Sound Barrier" as of now.

Lúcio gives himself and all allies he has line of sight to within 30 meters a large amount of temporary health, which rapidly decays.

Details from the wiki: At the time of writing, Sound Barrier grants 500 bonus health which decays over 6 seconds, i.e. losing about 83 of that health every second.

Order of application

It's perfectly possible in game to have all 4 of these health types at the same time, so it's worth noting how they interact when you receive damage.

Damage is absorbed in the following order. Once each level is depleted, damage will be applied to the next etc:

1. Overshield
2. Shield
3. Armour
4. Life

If there is not sufficient of one to cover the whole damage for a single hit the remainder will be applied to the next level.