Critical Chance

Critical Chance is a derived statistic in Fallout, Fallout 2, Fallout 3, Fallout Tactics and Fallout: Brotherhood of Steel.

Fallout, Fallout 2 and Fallout Tactics
The chance to cause a critical hit in combat is increased by this amount. An Aimed Shot has a higher chance to score a critical hit than an unaimed shot. In Fallout Tactics, the Science skill also apparently has an effect on critical chance against robotic enemies.


 * $$\text{Initial level}=\text{Luck}\times1\%$$


 * The Finesse trait increases the critical chance by 10%.
 * The More Criticals perk increases the critical chance by 5% per rank.
 * The Sniper perk increases the critical chance to 10*Luck for ranged weapons.
 * The Slayer perk increases the critical chance to 100% for melee weapons.

Base Chance
Luck in the main base factor that determines the chances of a critical strike on a opponent.


 * $$\text{Initial level}=\text{Luck}\times1\%$$

Example: A starting Luck of 5.


 * $$5\times 1=5\%~(\text{Base chance})$$

Notes:
 * Maximum initial base is capped at 10%.
 * Ninja perk can increase this limit by another +15% for Melee and Unarmed weapons.
 * Finesse perk can increase this limit by another +5%.
 * Survival Expert perk can increase this limit by another +3%.
 * Strikes dealt in V.A.T.S have additional +15% critical chance added.
 * Some weapons have 0% chance of a critical strike (see Critical Multiplier for detail of effects).

Critical Multiplier
All weapons have a critical multiplier that modifies the player's base critical chance to create a new percentage to score a critical hit. This may improve or hinder the player's ability to score a critical hit depending on the weapons Critical multiplier.


 * $$\text{Base chance}\times\text{Critical multiplier}$$

Example: A starting Luck of 5 and using a Sniper Rifle.


 * $$5\times 1=5\%~(\text{Base chance})\times5=25\%~(\text{Critical multiplier})$$

Notes
 * The critical multiplier for fully automatic weapons is much lower than for single-shot weapons.
 * There are a few weapons that have a x 0 multiplier, which makes it impossible to score a critical hit
 * For a detailed list of weapon critical multipliers see Fallout 3 weapons.

Weapon Condition
The final critical chance is also modified by weapon condition.


 * $$\mbox{Base chance} \times \mbox{Critical multiplier} \times \mbox{Condition}$$

For example, a character with 5 Luck and using a Sniper Rifle in 50% condition would have,


 * $$5\times 1=5\%~(\text{Base chance})\times5=25\%~(\text{Critical multiplier})\times50\%~(\text{Condition})=12.5\%~\text{Critical chance}$$

"Fallout New Vegas"
The formulas for critical chance seem unchanged from Fallout 3. You receive 1% of critical chance for each point placed into Luck. In character creation you can add an additional 3% for all weapons by choosing the Built to Destroy trait.

Perks that increase critical chance include:
 * Finesse (which affects all weapons)
 * Ninja (which only effects melee and unarmed attacks)
 * Laser Commander (which only affects laser energy weapons).

An item that increases critical chance (for all weapons) is the 1st Recon beret.

This means you can raise your critical chance to:
 * 23% for Guns and plasma Energy Weapons skill weapons.
 * 28% for laser Energy Weapons
 * 38% for Melee Weapons and Unarmed

Note: Factoring in the Critical Chance multiplier it is possilbe to achieve 100% Critical Chance with:


 * Guns
 * Sniper rifle (Fallout: New Vegas)
 * Gobi Campaign scout rifle
 * Ratslayer


 * Melee
 * Liberator
 * Figaro


 * Unarmed
 * Mantis gauntlet

Fallout: Brotherhood of Steel
In Fallout: Brotherhood of Steel, a critical hit allows to exceed the maximum limit of damage for a weapon.

Some weapons are very powerful with a high critical chance, such as the Double-Barrel Shotgun or The Slugger and also the weapons in bursts.

An energy weapon with the skill Energy Charge or a Melee weapon with the skill Special Attack can be extremely powerful if the charged attack is a critical hit.

The chance to cause a critical hit in combat is increased by

Initial Level: Each character starts with a 1% critical chance.


 * The Butcher skill (only Cain) increases the critical chance by 5% only for blades for each ranks until a total of 25%.
 * The Desert Soldier skill (only female character) increases the critical chance by 5% only for conventional weapons (weapon that uses 9mm) for each ranks until a total of 25%.
 * The Future Woman skill (only female character) increases the critical chance by 5% only for energy weapons for each ranks until a total of 25%.
 * The Heavy Hitter skill (only human male character) increases the critical chance by 5% only for Blunt weapon (Gloves, Clubs and Hammers) for each ranks until a total of 25%.
 * The Pyromaniac skill (only Cain) increases the critical chance by 5% when using a fire-based weapon (like the frag grenade, flamer, etc.) for each ranks until a total of 25%.
 * The Slayer skill increases the critical chance by 5% for each ranks until a total of 25%.
 * The Wastelander skill (only human male character) increases the critical chance by 10% only when using home-made weapons for each ranks until a total of 50%.

The type of weapon with a maximum critical chance with the skill required is the home-made weapons with a total of 75%.