Endurance

Endurance is one of the seven primary statistics in the SPECIAL system.

Fallout, Fallout 2, Fallout Tactics
Modifies: Hit Points, Poison & Radiation Resistance, Healing Rate, and the additional Hit Points per level.

Ways to increase Endurance

 * In Fallout, the Brotherhood of Steel in Lost Hills can perform an operation to permanently increase Endurance by 1, assuming the Vault Dweller can afford it.
 * Endurance can be permanently raised in Fallout 2 and Fallout Tactics via the Gain perk.
 * Endurance can be temporarily raised by 3 in Fallout and Fallout 2 by using Buffout.
 * The Elixir of Life from Fallout Tactics gives +1 EN and +15 HP.

Fallout 3
Modifies: Hit Points, Poison & Radiation resistance (but not damage resistance) and the Big Guns and Unarmed Skills. Endurance also determines the speed the character's oxygen counter counts down when they are holding their breath underwater.

Ways to increase Endurance

 * Permanent
 * Bobblehead - Endurance (+1)
 * Intense Training perk (+1)
 * No Weaknesses perk (will raise base to 5 if below 5.)
 * Almost Perfect perk (will raise base to 9 if below 9.)
 * Temporary
 * Armor and clothing
 * Brahmin-skin outfit, Mechanist's costume, wasteland settler outfit, wasteland wanderer outfit (+1)
 * Laborer outfit, tattered slave outfit, worn slave outfit (+1)
 * All-nighter nightwear (+1)
 * Buffout (+3)

Fallout: New Vegas
Endurance determines a character's environmental resistances (poison, radiation), Hit Points, and Healing Rate, as well as the starting levels of the Unarmed and Survival skills. It also determines the number of implants allowed.

Ways to increase Endurance

 * Permanent
 * Endurance Implant available at the New Vegas medical clinic (+1)
 * Intense Training perk (+1)
 * Completing the quest The Apocalypse or The End will allow raising any one primary statistic by 1.
 * Temporary
 * Armor and clothing
 * Brahmin-skin outfit, wasteland legend outfit, wasteland settler outfit, wasteland wanderer outfit (+1)
 * Atomic-valence tri-radii-oscillator, Valence radii-accentuator (+1)
 * Advanced riot gear, Courier duster, marked trooper armor (+1)
 * Traits
 * Claustrophobia (+1 while outdoors, but -1 indoors)
 * Early Bird (+2 between 6am and 12pm, but -1 between 6pm and 6am)
 * Buffout (+3)
 * Sierra Madre martini (+4)

Fallout 4
Modifies: Hit Points and the rate that Action Points deplete by while sprinting.


 * $$HitPoints = 80 + Endurance \times 5$$


 * $$HitPointsPerLevel = 2.5 + (Endurance \times .5)$$


 * $$TotalHitPoints = HitPoints + (HitPointsPerLevel \times (CurrentCharacterLevel - 1))$$

rounded down, i.e.:
 * $$TotalHitPoints = 77.5 + (4.5 \times E) + (2.5 \times L) + (0.5 \times E \times L)$$

rounded down, where E = Endurance and L = Current Character Level.

Leveling Up: In Fallout 4 Endurance is retroactive; increasing it later on in the game will still reward you all the hit points you would have gained with a higher initial statistic. An endurance of 10 will grant you 7.5 HP per level (or 7 and 8 every other level, since health is rounded down). It is possible to increase endurance beyond 10 permanently (e.g. picking up a vault tec bobblehead), which will allow the player to gain even more hp per level. There is no Hit Point Cap.

Sprinting

Action Point drain while sprinting:
 * $$ActionPointsPerSecond = (1.05 - 0.05 \times Endurance) \times 12.0$$

Moving Target adds an additional 0.5 multiplier

Game Settings for sprinting:
 * fSprintActionPointsDrainMult = 12.0
 * fSprintActionPointsEndBase = 1.05
 * fSprintActionPointsEndMult = -0.05

In layman's terms, 1 Endurance is equal to a default Action Point drain rate of 12 AP per second, with a reduction of 0.6 AP per second for every additional rank of Endurance, reducing the drain rate to 6.6 AP per second at 10 Endurance.

Note that with 1 Agility, the player has a maximum of 70 AP. This translates to 5.83 seconds of potential full sprinting time at 1 END, 6.14 at 2 END (+0.31 seconds of full sprint), 6.48 at 3 END (+0.34), up to 10.61 seconds at 10 END. However, each point in Agility raises the player's maximum AP by 10 points, which translates to 2 AGL granting 6.67 seconds at 1 END (+0.83), 3 AGL granting 7.5 seconds at 1 END (+0.83), and 10 Agility (160 AP) grants 13.33 seconds at 1 END (+0.83).

Mathematically-speaking, raising Agility is the better way to increase the total time you can sprint, at least until reaching a full sprint time threshold of 16.67 seconds, after which putting points into Endurance becomes more profitable. This threshold is reached at any allocation of 13 additional points into both END and AGL (i.e. END + AGL = 15, an 8:7, 9:6, or 10:5 distribution). These calculations do not include the multiplier added by Moving Target 3, which in turn has a prerequisite of 6 AGL, Level 44, and three ranks).
 * Since SPECIAL is by no means capped, it is possible to affect non-permanent stat increases beyond 10 (11 with bobbleheads obtained after reaching 10 through perk allocation) using equipment and consumables. Under this course of action, the multiplicative AP drain rate at END 14 and AGL 1 equals 200 max AP at END 1 and AGL 14 (16.67 secs of sprint either way) and at 16+ END increases sprint time by full seconds.

Fallout Shelter
Modifies: Dweller's maximum Hit Points.

On each level-up Dweller's maximum HP increases according formula:

$$MaxHitPoints += (BaseEndurance + OutfitEndurance) * 0.5 + 2.5$$;

Dwellers with higher Endurance perform better in Nuka-Cola bottler.

Ways to increase Endurance
By training Endurance in fitness room.
 * Permanent

By equipping outfits that raises Endurance, e.g. wasteland gear.
 * Temporary