Base on the data gathered by players from iCBT1 and kCBT3, im able to plot the Critical Rate vs Actual Critical Rate graph, and it appears to be a linear graph. (X-Critical Rate, Y-Actual Critical Rate)

2 of the formula are as below:

y = 95(X/175 - 1)

Character Level: 184 (Monk), Monster Level: 185 (Rambear), Crit Resist: 30, Crit Rate: 317, Actual Crit Rate: 85% (Info provided by the tester are limited and incomplete, the formula is questionable. http://www.tosbase.com/database/monsters/47462/)

y = 12(X/26 -1)

Character Level: 119 (Quarrel Shooter), Monster Level: 117 (Chronodog), Crit Resist: 26, Crit Rate: 196, Actual Crit Rate: 72% (according to the tester, the monster named Chronodog with 26 Crit Resist, located at MageTower 3F, monster record not found from ToSBase.com, but found a monster named Arma with Monster Level 119 and Crit Resistance 26 instead http://www.tosbase.com/database/monsters/47394/)

**This Section had proved to be wrong**

By factoring in Monster Critical Resistance, im guessing the formula is very close to this:

Actual Crit Rate = (Monster Level / 2) * ((Crit Rate / Crit Resist) - 1)

**Assumption of Crit Resist proved to be wrong and does not scale with Monster Level**

From the formula above:

Y = 95(X/175 - 1) = (19 / 35) * (X - 175)

Y = 12(X/26 -1) = (3 / 7) * (X - 26) = 0.4286 * (X - 26)

Hence, we can conclude the Critical Rate Formula:

**Actual Crit Rate = Variable1 * (Crit Rate - Variable2)**

*Variable1 believes to be a constant and different for each of the class

*Variable2 believes to be Monsterâ€™s Crit Resist

**Actual Crit Rate = N * (Crit Rate - Crit Resist)**

For Quarrel Shooter, N is around 0.4286

For example:

A Quarrel Shooter having 200 crit rate and the monster having 50 crit resist

Actual Crit Chance = 0.4286 * (200 - 50) = 64.29%

Crit rate to actual crit chance ratio = 1/0.4286 = 2.33

**After deduction of crit resist, every 2.33 crit rate will improve the actual crit chance by 1%**

Buff that affect Crit Resist - Zalciai (Krivis)

Lv5 -(12+SPR*0.8) Crit Resist, +(37+SPR) Crit Attack, 38s, 20s cd
Lv10 -(20+SPR*0.8) Crit Resist, +(69+SPR) Crit Attack, 58s, 20s cd

Lv15 -(28+SPR*0.8) Crit Resist, +(100+SPR) Crit Attack, 78s, 20s cd

(Attributes +9sec, +48 magic amplification)

Buff that affect Crit Rate - Monstrance (Priest)

+((DEX/10)*3+10)DEX, 20s, 23s cd for every levels

(Attributes +5sec)

Reference:

http://forum.gamer.com.tw/C.php?bsn=19840&snA=740&tnum=2

Reddit Discussion:

20160406 Update:

Actual Critical Rate = (Critical Rate - Critical Resist) * (42 / Character Level)

Source: Confirm by recent kOBT patch note on March 24 https://www.reddit.com/r/treeofsavior/comments/4bqxg5/ktos_324_weekly_patch/

Other Source: Critical rate formula (iCBT2 updated)