One of the most common questions when comparing armor items of similar quality, is which is better for protection: armor, stamina or health? Well, I have good news because Division Field Guide is going to help make that decision far less time consuming for you.
For the math geeks out there, there are a few equations that are significant when making these comparisons. The first is to convert stamina into health since they are not 1 for 1, but it is quite simple.
Health = Stamina * 30
In The Division, your total Health / Hit Points is calculated by adding up all of the Stamina received by all Armor Items and their mods multiplied by any mods offering a percentage based increase in health. The formula would then be:
Total Health = (Total Stamina * 30 + Total Flat Health Bonus) * (1 + Health Percentage Bonus Mod)
Similar to Health, Armor needs to be calculated across all items and mods but it also needs to be converted to a percentage value which is used to determine how much of an attackers damage will lower your health. This value is called Damage Mitigation.
Total Armor = (Base Armor Items + Total Bonus Armor Items) * (1 + Armor Percentage Bonus Mod)
The Total Armor Damage Mitigation calculation is a bit more complicated. It involves a base value that is tiered based on level and another one that is scaled with your level. It also involves any bonuses from talents. Please keep in mind the maximum Damage Mitigation from Armor was 65% (4640 armor), but has been raised with v1.2, Conflict, to 75% (5354 armor)
Tiered Base Value:
level = 1 - 600
level = 2 - 580
level = 3 - 560
level = 4 - 540
level = 5 - 520
level >= 6 && level <= 29 - 500
level >= 30 - 450
Total Armor Damage Mitigation = (Total Armor / (1.1 ^ (Agent Level - 1) + Tiered Base Value) + Talent Flat Percentage Bonus) * (1 + Talent Percentage Bonus)
Finally we bring it all together to determine which is better based on how much attack damage is required to send you into DBNO (down but not out) state. This calculation is fairly simple:
Damage to DBNO = Total Health / (1 - Total Armor Damage Mitigation)
Health regeneration is based on your total health and whether or not you are in combat. Armor has no impact on health regeneration and technically stamina has only an indirect relationship.
For the tl;dr; readers, it depends on an items attributes, so you need to look at how each item effects your overall attributes. To determine which item you have that offers the best protection against going DBNO (down but not out), you just need your total health and total damage mitigation from armor while wearing each item. Both values are easily accessible within the Character tab of your Inventory, under the section called Survivability.
To help you with your decision making, we have created our first calculator for the game which allows you to input a few values and compare how it will impact your combat effectiveness, Survivability Calculator. Just plug those total health and total damage mitigation values while wearing each item into our calculator to see how much damage is required to put you into DBNO and what your health regen rate would be. Then you can make an informed decision.