Damage 1.0

Damage in Warframe can be broken down into 15 damage types: Armor Piercing, Blade, Bullet, Electricity, Explosion, Fire, Forcefield, Freeze, Impact, Laser, Physics Impact, Poison, Serrated Blade, Stun, and Supernatural (there are possibly more). Different factions and different enemy bodyparts may be resistant or vulnerable to a specific damage type. Moreover, four of these damage types regularly ignore the armor of enemies: Armor Piercing, Physics Impact, Poison and Serrated Blade.

Damage is displayed on the HUD as numbers that spawn near the point of impact on an enemy. Damage to health is shown in a white, while damage to shields is shown as a blue. Damage can also produce critical hits. Critical hit damage, melee damage dealt while using Stealth, or damage done while undetected are displayed as a yellow. Finally, melee critical hits while stealthed are shown in red. Additionally, some melee weapons can produce critical hits in red without its user being stealthed.

Each of the damage types will spawn a separate number indicator. Shotguns will also spawn separate indicators for each of their pellets. Damage that is reduced to zero, such as Bullet damage on a Crewman's head, will not spawn a number indicator.

Damage types
(under construction)

Armor Piercing
Damage of this type uses the Armor Piercing Mechanic.
 * Despair
 * Snipertron
 * Snipertron Vandal

Blade
Also known as slashing damage, damage of this type dismembers foes, and does 3x damage to infested. Ironically the Dread uses this damage type, while all other weapons of this category are blades.
 * Dread

Bullet
Also known as normal damage, this is the standard damage type.
 * Afuris
 * Aklato
 * Boar
 * Braton
 * Braton Prime
 * Braton Vandal
 * Bronco
 * Bronco Prime
 * Burst Lasor Pistol
 * Burston
 * Decoy Pistol
 * Deth Machine Rifle
 * Dual Broncos
 * Furis
 * Gorgon
 * Grakata
 * Kraken
 * Laser Rifle
 * Lato
 * Lato Prime
 * Lato Vandal
 * Latron
 * Latron Prime
 * Lex
 * MK-1 Braton
 * Seer
 * Sicarus
 * Strun
 * Supra
 * Twin Vipers
 * Viper
 * Vulkar

Fire

 * Ignis

Forcefield
Damage of this type ragdolls enemies.
 * Kogake

Impact

 * Hek
 * Sobek

Laser

 * Dera

Physics Impact
Also known as "bolt" weapons, this damage type allows projectiles to go launch enemies back, dealing damage to those behind them.
 * Akbolto
 * Bolto
 * Boltor
 * Kunai
 * Paris
 * Paris Prime

Poison

 * Acrid

Serrated Blade

 * Flux Rifle
 * Hikou
 * Lanka
 * Spectra

Calculating Base Damage
The first thing to remember is that damage types do not do anything themselves except for define the damage type, and Mods do nothing except for create a new base-damage for that damage type to be applied. Other than that, any other calculations are entirely dependent on the target.

The second thing to remember, and the first thing to figure out when calculating base damage, is that there is no such thing as "Armor Ignoring" damage. In reality, each target has a list of damage types that it will not apply armor to. In generally, these damage types include:


 * Armor Piercing (ie: Snipetron, Despair,  Piercing Hit)


 * Physics Impact (ie: Boltor, Kunai, Paris)


 * Poison (ie: Torid, Acrid, Mire)


 * Serrated Blade (ie: Most (but not all) mele charge attacks, and the Lanka...).

The last thing to find out before calculating damage is whether or not your targets body part that you are hitting is "protected" or not, meaning, "Will armor be applied to hits on this body part or not?". While grineer heads are still protected, ancient limbs are not, which explains why their damage scales the way it does.

Now that we know this information, we can start throwing around some numbers. Remember, if the target does not apply armor to your damage type, then do not include the "(100 / (target armor + 100)" section.  To your calculations.  Damage done = (weapon damage) * (1 + mod value) * (100 / (target armor + 100)) * (damage type mp) * (special spot mp)
 * Weapon Damage: determined by the equipped weapon. There is no range of damage in Warframe; all weapons will always deal a set amount equal to what is listed on their tooltip.
 * "Base Damage"
 * Mod Value: determined by the rank of the equipped "damage" mod (any modifications made by Serration, Hornet Strike, Point Blank, or Pressure Point/Killing Blow), if any.
 * Target's Armor: This is the value of the enemies armor (changes with level).
 * Damage Type MP(Multiplier): This is the value that the target has to multiply any incoming damage of this type.
 * Special Spot MP(Multiplier): This is the value that the target has to multiply any incoming damage to this body part (ie: head, moa' fannypack).

The mods that alter base damage are as follows:

 * Rifles: Serration
 * Shotguns: Point Blank
 * Pistols: Hornet Strike
 * Melee: Killing Blow and Pressure Point

Critical Hits
Most sources of damage can critically hit for additional damage. Each weapon attack, or each pellet in the case shotguns, has a separate chance to critically hit. Elemental mods will only critically hit when the weapon itself does, however they will be multiplied by the same amount. Stealthing does not appear to affect critical hit chances, but does provide a 50% damage bonus to all melee attacks, which may cause players to assume that a critical hit has occurred.

Calculating Elemental Damage
Each elemental damage bonus on a weapon will add a separately calculated bonus hit to an attack. Different elemental damages will not interfere with each other or with a weapon's normal damage. Includes: armor piercing, electrical, fire, freeze, and poison.

As far as calculation of final damage dealt by the mod, it's the exact same formula as base damage, just multiply the damage % of the elemental mod as well (ie: 60% (.6) for Piercing Hit).

Multishot
Multishot is a feature that weapons do not normally possess, but can be added through weapon type specific mods (Split Chamber, Hell's Chamber and Barrel Diffusion). Multishot can add one or more additional projectiles to each shot fired, depending on the rank of the mod and the type of weapon. These additional projectiles do not consume any extra ammunition.

Stealth Attacks
Melee attacks while stealthed deal 150% of the total damage they would normally do. Stealth attacks generate yellow hit indicators, the same color as critical hits, even though they are not actual critical hits. True melee critical hits while stealthed can by identified by their red hit indicators.

As long as players on a mission remain undetected through the use of stealth, they can perform melee attacks that deal increased damage to their enemies. Non-melee weapons are not eligible for a stealth damage increase. Even after a mission's enemies go on alert, temporary stealth can also be achieved through the use Loki's Invisibility and Ash's Smoke Screen. Shade's Ghost is disrupted if owner attacks, therefore it does not grant any stealth attack bonuses.

Damaging Shields
While an enemy is protected from shields, any damage they take will not be affected by armor or resistance values. Moreover, damage to the weak points will not result in additional damage. Shields take 100% damage from all damage types except Freeze, which will deal 2x damage. Shielded enemies are also immune to critical hits and additional damage caused by stealth attacks until shields are broken.

After the shields of an enemy are depleted, any remaining damage amount is reduced by a value of one and run through the regular damage formulas to calculate damage taken as it normally would have occurred after taking into account critical hits, resistances, and weak points.

Warframe Powers
Damaging warframe powers determine their damage, critical rate, and critical damage through the equipped power mod. The power's damage type will determine whether or not an enemy will apply armor to it or not, just like damage from other sources. Similarly, enemy elemental damage type multipliers affect power damage. Lastly, Warframe Powers that are AoE or have no manual targetting will hit the torso of the enemy (fanny pack on corpus moa's) and follow the body part multipliers for that body part (explaining the 3x damage to corpus moa's).

See the individual warframe articles for information on how each power handles its damage.