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.

Initial Level: Starting critical chance is equal to your Luck. Average characters will have a 5% critical chance.


 * 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.


 * $$\text{Initial level}=\text{Luck}\times 1$$

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: 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%.