Previously this page had charts that listed a number of percentages for a small number of damage types that were found in the game. These percentages were incorrect and a misrepresentation of how damage actually works in the game. There are no such things as "resistances" in this game. Any damage an enemy incurs is put through its Armor calculation with two exceptions:
1) If it is an ignored damage types, which include
- Armor Piercing (i.e.:
Snipetron, 
Despair, 
Piercing Hit) - Physics Impact (i.e.: Boltor, Kunai, Paris)
- Poison (i.e.: Torid, Acrid, Mire)
- Serrated Blade (i.e.: Most (but not all) melee charge attacks as well as Hikou, Flux Rifle, Spectra and Lanka)
Note: the only exception to this is the absense of Physics Impact on the Grineer Commander, Seeker, and Roller.
2) If you are firing at an unprotected body part.
When firing at protected body parts, all other damage types, including fire, frost and electrical Elemental Damage mods are subject to armor calculations, which is why they will scale to the level of the enemy. Please see the game mechanic pages linked above for information on how these calculations work. The armor calculation is as follows:
Armor Mitigation = 100 / ((base armor + base armor * .01 * (current level - base level) ^ 1.40) + 100)
Once the armor mitigation is applied to damage, the damage type and hit location multipliers are applied. These multipliers stack. The multipliers affect the slope (and rate of change of the slope) of the output graphs - so this will change depending on the damage type and where you hit the enemy. These multipliers in combination with the armor calculation are what people misinterpreted as "resistances" in the game.
It should also be noted that vulnerabilites are different than how difficult an enemy feels in the game. For example, Elite Grineer Lancers feel much more difficult than Grineer Lancers because they have higher base HP and Shields. However, both of these enemies share identical vulnerabilities to damage. This logic also applies to Corpus Techs and other Corpus Crew.
Shields[]
Shields do not apply any of these armor calculations or regular damage type multipliers. Shields take full damage from all damage types; with the exception of Freeze Damage, which does 200% damage to shields.
Examples:
- if you shoot a Medium Grineer in the head with bullet damage, the armor mitigation will be applied, then the x2 head MP and the x1.5 bullet to the head MP will be applied.
- If you shoot a Medium Grineer in the head with armor piercing damage, armor will not be applied (because it is an ignored damage type), and then the head and armor piercing damage MP will be applied.
- If you used these same damage types on a Medium Grineer for a body shot, the armor mitigation portion of the calculation would not change but you would lose the head MP and only the armor piercing MP would be applied because the bullet MP is only for head shots.
- If you shoot an Ancient in the lower leg with fire damage, armor will not be applied because it is an unprotected body part, then the x2 fire MP will be applied.