The chance is not 2.5%, but instead is a multiplier to the catch rate, *a.* Here is the formula:

*a* is the overall catch rate.

*HPmax* is the maximum health of the Pokemon. In this case, let's say you caught Level 50 Munna. With 0 EVs and 0-31 IVs, this ranges from 136 to 151.5.

*HPcurrent* is the current health of the Pokemon. Since you use Super Fang, this will be 1/2 of HPmax.

*rate* is the catch rate of the Pokemon. Munna's is 190.

*BONUSball* is the Poke Ball's multiplier. The Ultra Ball's is 2.

*BONUSstatus* is the current status of the Pokemon. Since it is asleep, this value is 2.5.

Plugging this all in, we get a equal 633.3333...

But what does that have to do with anything? Well, for critical captures, a number between 0 and 2047 is generated. If this is less than *a* times the multiplier *(in this case, 2.5)*, a critical capture will occur.

*a* times 2.5 is 1583.3333... Therefore, Critical Captures have about a 77.35% chance of occurring under your conditions.

Since you got the captures 16 times in a row, your formula would be (0.7735)^16, resulting in a...

### 1.641969510729874658525195052896% chance of occurring.

**Source**