Is there something missing from the Pokemon Capture Formula?

[ZONexus]

Please correct me if I am wrong, but shouldn't any pokemon with their Personal Catch value of 255 always be caught?

(looking at the formula in theory any pokemon with a catch value of 128 or higher should always be caught even at full health).

So why can a Pokeball fail?

*By catch Value I mean the "Catch Rate" value that is to be inserted into the formula.

 

[Nekusagi]

...twitches...

Explain more how you worked this out, onegai.

 

[Zhen Lin]

Um, yes, there seems to be something wrong with it. It should be impossible to not catch Caterpie, Weedle, Pidgey etc. (catch rate 255) yet it happens.

The Internet Archive isn't working for me now, but look for the old Pokémon Forever there - it may have the correct formula.

 

[ZONexus]

I guess I could try and explain...

Again please correct me if I am wrong

According to http://bulbapedia.bulbagarden.net/wiki/Catch_rate

Chance = floor (((( TotalHP * 4 ) - ( CurrentHP * 2 )) * CatchRate ) / TotalHP ) + Status + 1
and a Random number between 0 and 255 is generated and if it is less than the “Chance” the pokemon will be caught

For this argument we can let “TotalHP” and “Current HP” be equal and henceforth both will be referred to as “X”.
We will assume there is also no status bonus so “Status” is equal to 0.
and let “CatchRate” be Y.

So the equation takes the form of

Chance = floor((((4X)-(2X))*Y)/X)+0+1
and simplifying
Chance = floor(((2X)*Y)/X)+1
Chance = floor((2XY)/X)+1
Chance = floor(2Y)+1

So if 256 is a guarantee capture
256 = floor(2Y)+1
255 = floor(2Y)
255/2 = floor(Y)
127.5 = floor(Y)
128 = Y



*On a Side note wouldn’t it be easier to express the Formula as
Chance = floor(2CatchRate(2-(CurrentHP/TotalHP)))+Status+1

and based on that the lowest Chance is “2CatchRate+1” and the Highest is “4CatchRate+10”

**This is all without taking the ball into consideration

 

[Zhen Lin]

Well, game arithmetic has its little rounding errors, so it's not quite the same.