Often confused with Constitution, Health is the total amount of damage a Champion can take before dying. While Constitution is one of the factors in determining total Health, other factors also play a part.
This stat can be increased through Equipment that have the proper Runes, skills such as the Warrior's "Battle Hardened" and the Rouge's "Knife Artist" and specific Trinkets.
The formula below shows how Health is calculated:
Base Health = (Constitution + Level) * (Class Modification) * 8
Total Health= Base Health*(Hp Bonus+1)
Also could use this calc .
Class Modification is the specific value of a Class' affinity with Constitution and their values can be seen below:
Warrior : 220% (2.2 in Formula)
Mage : 165% (1.65 in Formula)
Rogue : 150% (1.5 in Formula)
As shown, Warriors have the highest Class Modification value and have the most affinity to Constitution. As such they can be made into superior Tanks compared to other Classes when heavily invested in Constitution. Although resistances are also important in having a well bult tank.