DISCLAIMER: All of the information in these journals will be based on the mechanics of the Generation 6 games (XY and Omega Ruby/Alpha Sapphire), so some finer details MAY be changed in Generation 7 (Sun/Moon). I also do not claim to be the person who discovered any of this information. Everything I have learned is aggregated knowledge from sites such as (But not limited to) Serebii, Bulbapedia and Smogon.
This first journal is going to be all about the most well known aspect of Pokemon; Capturing! I'm going to very thoroughly explain the process that goes through the game EVERY SINGLE TIME you attempt to capture a Pokemon... And let me warn you now, there WILL be math.
And before anyone asks or tries to say otherwise...
Pressing and/or holding A/Down+A, B/Down+B or any other button/combination of buttons DOES NOT IMPROVE THE ODDS OF CAPTURE AT ALL.
It may make you feel better to do it (Personally, I begin holding A as soon as the ball opens and pulls the Pokemon in), but just know it has no REAL effect whatsoever.
Ever since Pokemon first became a thing the very name itself was secondary only to its catchphrase/tagline; "Gotta catch 'em all!" Anyone who has spent any amount of time with the games knows that capturing wild Pokemon is very nearly the core mechanic of the series, potentially even moreso than battles as the series typically introduces 100+ new Pokemon with each generation of games that are released.
Likewise, the people who've played the games probably know already that the key to capturing a Pokemon is to weaken it first THEN throw a Pokeball at it. Also it's very likely they know that Great Balls and better than Pokeballs, and Ultra Balls better than Great Balls. However, did you know that a sleeping Pokemon is easier to catch than one suffering from paralysis? Or that a Quick Ball is twice as effective as an Ultra Ball but ONLY on the first few turns?
More importantly, did you know that there is an actual mathematical formula that the game follows to determine your odds of successfully capturing a Pokemon? It's actually surprisingly simple (At least I thought so), and you can figure it out yourself before you even throw the Pokeball! The ONLY difficult factor you have to figure out is what the target Pokemon's maximum HP is, since you can't see a numeric value of such UNTIL you've captured it.
Let's begin with the simple stuff though, which is what you CAN see and have control over.
First is the most obvious to all the veteran trainers out there; Weakening the enemy Pokemon. The more HP you can knock off of an enemy without making them faint, the better chance you have of capturing them! Health bars in Pokemon have three stages, which are conveniently color-coded so you CAN track them. If the Pokemon has more than half their HP, the bar remains green. Between 50% and 26% percent HP the bar turns yellow, and between 0% and 25% the bar becomes red. Again, the further into the red a Pokemon is, the better your chance of a successful capture... And trust me when I say that it REALLY matters more than you might think.
Second is a factor that, surprisingly, a large number of players aren't aware of; Status effects. Once again, veteran trainers are probably keenly aware of what it means to have a Pokemon be paralyzed or poisoned, but those same status effects and all the others can GREATLY alter your chances of a successful capture!
The base for a Pokemon with NO status effects upon it is of course 1.0x, because mathematically speaking anything multiplied by 1 does not change (You'll see a few 1.0x multipliers throughout this post for that reason). The status effects of Burn, Poison and Paralysis will all add 1.5x, or 50%. Frozen and Sleep, however, provide a 2.0x, or 100%, increase!
A third factor that even LESS people are aware of is something called O-Powers. Introduced in XY, O-Powers are temporary boosts for various in-game things that you can use to give yourself an advantage! O-Powers have three levels (And two more beyond that, though they're exceptionally difficult to get as one is only available from physical Pokemon Center stores and the other you can only get as a one-time use from Secret Base Pals once you hit Secret Base Platinum, which requires some 1000 flags) and each level is more helpful than the one before it. There are many O-Powers, and most you have to obtain from an in-game character by speaking with them.
Fortunately, in both XY and ORAS, the Capture O-Power is available right away. In XY you get it as soon as you receive your starter Pokemon, and in ORAS you get it as soon as you obtain the PlayNav (Which you need in order to access O-Powers anyways). To find this and other O-Powers, open the Player Search System (PSS) on the touch screen. You will see a folder with dots upon it, which you need to tap and then from the screen that opens progress to the second page. There you will find the O-Power option, which you can tap on to see your list of O-Powers!
There IS a catch though, two in fact.
First is that O-Powers have a "cooldown" of sorts. Notice at the bottom of the touchscreen there are 10 green dots. Each time you use an O-Power it costs a certain amount of these dots, and using it for others costs less than using it for yourself. Capture O-Power, for instance, will cost four points at Level 1, five at Level 2 and six at Level 3. O-Powers only last for three minutes, but it takes four minutes to refill a single circle (The recharge time of the circles can be sped up by walking in the real world and adding steps to your 3DS' built-in pedometer. 2001-3000 steps gives 2x regeneration, 3001-4000 gives 3x and 4000+ gives 4x).
The second catch is HOW your O-Powers are leveled up. To level up an O-Power you must use it a certain amount of times. To advance to Level 2 you must use the Level 1 O-Power 15 times, and for Level 3 you must use the Level 2 version 30 times. You CAN boost this quite easily by simply using the O-Power you wish to level up over and over again, as you never need to make USE of its effects and instead simply use it AT ALL. It is also much faster to gift the O-Power to others as it will cost less each time, but this method requires you to be online.
Capture O-Power affects your capture rate as follows:
No O-Power: 1.0x catch rate
Level 1: 1.5x catch rate
Level 2: 2.0x catch rate
Level 3: 2.5x catch rate
Finally, the last factor you can actively control; Your ball of choice. Yet again I don't imagine this is news to people who have PLAYED the games at length before, BUT what even some of those players may not be aware of is JUST how much each ball affects the capture odds. Bear with me as I list every ball you can purchase/obtain and their rate modifiers:
Poké Ball: 1.0x
Premier Ball: 1.0x
Heal Ball: 1.0x AND fully heals the captured Pokémon
Luxury Ball: 1.0x AND the Pokémon will gain Happiness points more quickly
Timer Ball: 1.0x BUT it increases by 0.1x every turn, up to 4.0x after 30 turns
Great Ball: 1.5x
Safari Ball: 1.5x
Ultra Ball: 2.0x
Nest Ball: Rate is equal to 40, minus the opponent's level, divided by 10. Cannot go below 1.0x and 3.0x is the maximum
Repeat Ball: 3.0x IF you've caught another of the Pokemon's species before, otherwise 1.0x
Net Ball: 3.0x ONLY for Bug and Water-type Pokémon, otherwise 1.0x
Dive Ball: 3.5x ONLY on Pokémon found underwater (Meaning you must have entered the battle while fishing, Surfing or Diving), otherwise 1.0x
Dusk Ball: 3.5x ONLY at nighttime (After 9:00 PM) or in caves
Quick Ball: 4.0x for the first five turns, otherwise 1.0x
Master Ball: 255.0x
Now I know what some of you may be thinking: "I thought the Master Ball was a GUARANTEED capture?!" Fret not, because due to math and some smart programming it WILL always succeed... But were the smart programming not in place there would actually be a chance that the Master Ball could fail! I'll explain what I mean in a few moments.
Beyond this point will be the part where MOST of you never need worry about anything else. As long as you're utilizing the information above this point, you should be as well off in terms of capturing prowess as someone who bothers to learn the details below this point...
But learning never hurt anyone, right?
Next are the two things you CANNOT control, the factors that are also essentially "hidden" as you can't find them in the visible game itself.
The first is one I already discussed, the enemy's maximum HP. Due to Individual Values (IVs) you can never be 100% sure of a Pokemon's stats until you view them via the menus. That said. there ARE ways to more or less accurately guesstimate the Pokemon's max HP (Just Google Pokemon base stat calculators), but I'm not going to go into all of that since there's ALREADY more than enough to explain in this journal.
The second is the biggest factor, capture rates, and you've probably heard the term mentioned many times albeit whether or not it was in relation to THIS particular meaning. Every single Pokemon has a hidden base capture rate; An assigned and unchangeable numeric value between 3 and 255. Pokemon such as Caterpie and Rattata are on the 255 end of the spectrum, while Legendary Pokemon like Mewtwo have a base capture rate of 3.
As you may be able to discern, a smaller capture rate means the Pokemon will be naturally more difficult to capture. Outside of those Legendaries with a value of 3, capture rates are ALWAYS a multiple of 5. Remember the "smart programming" I mentioned? I was referring to the fact that the LOWEST base capture rate is 3. Don't worry, you'll get even MORE explanation shortly.
Now we come to the scary part; The math. Pay close attention, as this is probably THE MOST math you'll ever see in your adult life (Unless you're, like, an engineer or something).
Allow me to present to you the primary formula of Pokemon capture:
If the final value of the above formula is equal to or greater than 255 (You almost ALWAYS round down, or otherwise ignore the decimal points), the capture is 100% guaranteed the second you throw the ball of your choice, and the game does no further calculations. If not... Well that's why we've designated the final value of the formula above as "mCR" which stands for "modified capture rate," because if things aren't already complex enough there's a secondary formula that comes into play, but again that is ONLY if the above value is anything less than 255.
Before that though, going back to that Master Ball topic, THIS is why no Pokemon has a base capture rate lower than 3. Assuming all the other values are correct and actually possible (IE as long as the Pokemon's current HP is not SOMEHOW higher than its maximum HP), plugging the Master Ball's 255.0x modifier into the formula will ALWAYS produce a number greater than 255. The only exceptions are the Pokemon whose base capture rate is 3, in which case the lowest number the math can reach is EXACTLY 255. This means that a Master Ball, mathematically, CANNOT fail to capture a Pokemon that is coded by proper programming (Not hacked, in other words).
So what if the value of the above formula IS less than 255? If such is the case, it becomes a game of chance that actually takes place during the moments when you see the Pokeball shake!
You may have heard it said in the past that the number of times a Pokeball shakes is completely random and has NOTHING to do with how close you are to capturing it... Well it's time someone finally told you that this statement is only a HALF-truth! While it IS based on random chance if the Pokemon will break out on any given shake, the number of shakes where the Pokemon does NOT break out are actually directly related to how good YOU have made your odds based on the factors you can control!
The reason why is simple; Because you carry over the value of mCR into this secondary formula;
We are calling this formula's final value "T," for threshold. Before each shake and then once more before the capture finalizes (A total of four times) the game generates a random number between 0 and 65536. If the number generated is less than the threshold determined by the previous formula, the check is a success and the Pokemon stays in the ball and you see it shake on-screen, then the game generates a new number to check against this threshold before the next shake. However, if at any point the generated number is equal to or greater than this threshold, the check fails and the Pokemon breaks free before the shake occurs on-screen.
See what I mean? Random chance due to RNG checks, but YOUR efforts increase the potential amount of shakes by improving your odds via giving you a more forgiving margin.
Conversely, you can figure out a rough percentage of your odds by dividing this threshold result by 65536, then taking that result and moving the decimal point two spaces to the right, which will be your percentage of each shake being successful.
However, and I cannot stress this enough, it is a VERY rough estimate simply because of the way random chance behaves. In the most simplified terms, 99% STILL leaves a 1% room for error, and if you happen to be unlucky you could find yourself in that 1% gap MORE than 1 out of 100 times. Statistically the odds may be in your favor, but statistics just plain cannot account for a stroke of bad luck.
Of related note to this threshold formula, there IS one other factor you can control, and you may have experienced it happen firsthand. You throw a Pokeball at your target, but as it flies through the air you hear a high-pitched, electronic whistle. After pulling the Pokemon inside, the ball pauses and shakes midair for just a moment before falling to the ground, after which it only gives a single shake before finalizing the capture! This is called a Critical Capture, and the chance of it happening each time you throw a Pokeball is directly related to how many Pokemon you have registered as "Caught" in your Pokedex.
Critical captures are VERY desirable, because they affect the number of times the game checks your threshold against a random number. Instead of performing four RNG checks like normal, a Critical Capture forces the game to perform ONLY A SINGLE CHECK against your threshold, giving the Pokemon less chance to escape! Of course though, the odds of a Critical Capture occurring at all involves MORE math, but fortunately this time it's a slightly easier formula.
First you take either the value of mCR OR 255, whichever number is smaller, then plug that number into this formula:
As stated earlier, your chances of getting a Critical Capture (Denoted as CC in the graphic) are based on how many Pokemon you've caught according to your Pokedex. The value of P within the formula is determined based on the chart below:
Less than 30 caught: 0
30-150 caught: 0.5
151-300 caught: 1.0
301-450 caught: 1.5
451-600 caught: 2.0
Over 600 caught: 2.5
Once you have the value of CC, the game once again generates a random number, this time between 0 and 255. If the CC value is higher than the random number, you'll throw a Critical Capture! Just like with the shake checks you can simply divide the solution to this formula by the maximum check number, which is 255, and on THAT solution move the decimal point two spaces right and you'll have a general percentage for your chance of each ball being a Critical Capture.
However, due to the math involved, the highest chance (On non-guaranteed captures) you can have of throwing a Critical Capture is about 41.67%. That percentage, however, can drop significantly depending on WHAT you're trying to capture BECAUSE it uses your mCR value!
The math is set up in such a way that you have very low odds of throwing Critical Captures against Legendary Pokemon, for example (The highest chance you can get against one is about 8.72%). Critical captures can and will still occur if your mCR goes over 255, even though at that point the shakes are superficial and so the Critical Capture is nothing more than an extra animation.
So what say we make some sense out of those formulas up there in the most obvious way possible; Examples! Personally speaking, my brain was nearly set to implode when I looked at those formulas the first time, BUT after plugging in the appropriate values and working through the math (Albeit with a scientific calculator) EVERYTHING made a surprising amount of sense... Both in what I was seeing AND what I had been experiencing in the games up to now.
Let's use four example Pokemon; Horsea, Clefairy, Eevee and Mewtwo (Capture rates of 225, 150, 45 and 3 respectively). Let's say we're attempting to capture each at 25% HP, while they are asleep. We'll first start with a regular Pokeball, and from there tweak the situation as needed. I'm also NOT going to bother with Critical Capture and/or O-Power factors on any of these, because I'm lazy and also because the math is already complex enough.
Sorry in advance as well, as this part may get a little long since I'm going to show each step AND I'm not going to bother rounding anything down until the end. I PROMISE though that seeing the numbers in practice makes everything WAY easier to follow!
I'm also going to use text instead of graphics from here onwards, because it's WAY easier to type these things than it is to make them in a visual program.
We'll start with the poster-child of capturable Legendaries, the hardest in our list of four to capture; Mewtwo, with a base capture rate of 3.
I'm basing the max HP off the one I personally caught in XY at level 70 and never once used, meaning it's HP is unaltered from when I first caught it.
First with a Pokeball:
mCR = 5.0042918454935622317596566523605
Ouch, just over a value of 5 for capture rate, and remember that Mewtwo STARTS at a base of 3! Also remember that 255 is a guaranteed capture, so barring that the closer you can get to 255 the better your chances are during the second formula...
And speaking of that second formula, since we DIDN'T get a 255 we now have to plug that mCR value into such for the shake checks:
T = 31360.313085054678798317819079934
So now the game will generate a random number up to 65536 before each shake and then once more before the capture is finalized. For Mewtwo to be captured, this random number has to be less than 31360 on EACH check. That's about a 53% chance on each check that Mewtwo will break out of the ball, or a very rough 6% chance overall that the capture will succeed.
Now let's try an Ultra Ball:
mCR = 10.008583690987124463519313304721
As you can see, the Ultra Ball does EXACTLY as advertised and doubles the capture rate, bringing us to about 10 or so.
Still not 255, so let's move on to the shake checks:
T = 35712.768123671830653045003243194
You'll notice HERE, however, that the math doesn't do us any favors. With an addition of 4352 to our threshold, the chance that Mewtwo will escape on each shake only drops to 46%.
You know what? We can do better! Let's add one more for Mewtwo where it's still asleep BUT we've brought it down to exactly 1HP and have started using Dusk Balls since it's in a cave:
mCR = 20.939914163090128755364806866953
I'll be damned, we've nearly doubled the capture rate AGAIN (And I honestly didn't know this would be the case in advance)!
T = 41014.407305826645647190919737736
We've increased our threshold by 5302, meaning now the game has to throw a 41014 or higher for the check to fail! Mewtwo now only has a 38% chance to escape on each check... But remember that the game generates FOUR random numbers between 0 and 65536, so if ANY of those are over our 41014 then Mewtwo escapes.
For the record, if you add a Level 3 Capture O-Power, your threshold is instead around 46706, which leaves Mewtwo with about a 29% chance to escape per each shake check. STILL not great odds when Mewtwo has four chances to hit anything above your threshold.
NOW all of you veterans out there can see why it's so damn hard to capture a Legendary even when you've tilted the odds as far in your favor as you possibly can. Legendary Pokemon are specifically programmed to be difficult to capture no matter WHAT you do, and there's no getting around it unless you use a Master Ball.
So let's move on to something a bit easier, not to mention more coveted by the casual player; Eevee! With a capture rate of 45, Eevee has the same chances of being caught as the story-required Legendaries in XY (Xerneas and Yvetal) and BW(2) (Reshiram, Zekrom and Kyurem). Compare the numbers to Mewtwo's once we're done here and you can see how Game Freak have been making the games slightly easier over the years!
Once again I'm basing the max HP off one I caught in-game, specifically FOR this journal, at level 8 from Route 116 in Omega Ruby.
Like before, we'll start with a Pokeball:
mCR = 78.75
Remember how low Mewtwo's mCR was even at our best odds? The 42 points between Mewtwo and Eevee's base capture rates makes a world of difference, doesn't it?
78 isn't 255 though, so you know what to do:
T = 52577.584163706250378321966225949
As you can see, we're already MUCH closer to 65536 than we ever could have gotten with Mewtwo. Eevee only has about a 20% of escaping on each shake check, and may I remind you this is with your average Pokeball and Eevee still with 25% of its health.
While you probably wouldn't need to use it, lets make an example with an Ultra Ball:
mCR = 150
Once more, the Ultra Ball nearly doubles the capture rate number that a Pokeball gives.
We're getting closer to 255, but we're not there yet:
T = 59329.509499100695900175821493333
The game now only has 6207 numbers that can be generated to allow Eevee to escape, meaning your chances just went up to around 90% per shake that Eevee will stay inside!
I won't show the math for it, but when I caught my Eevee for this example I did the same thing as the previous example, except I took it down to 1HP instead of letting it stay at 25%. The final values for this were an mCR of about 175 and a threshold of about 61116, which left it with about a 7.75% chance of escaping upon each shake.
The differences may be small on a localized, per-capture scale, but as the math shows EVERY little bit helps in the long run.
Of course though, Eevee was harder to come by in the past. Used to be you could only get an Eevee from the Game Corner, or even could only be given an Eevee and it was the ONLY ONE in the game you would ever get. This was solved with breeding and eventually Eevee being capturable in the wild... But there were still Pokemon back in those days that were hard to come by even though you could ONLY find them in the wild.
The Pokemon I'm talking about is, of course, Clefairy! We've only been discussing capture rates thus far, but APPEARANCE rates are a thing as well... But don't worry, I'm not getting into THOSE numbers. In the early games you only had about a 5-6% chance of finding a Clefairy in the wild, which was made worse by the fact that Clefairy only showed up in two or three places in the entire game! Even without modern in-game tools such as the Pokeradar or the DexNav, which both pretty much guarantee you a chance to find what you want, Clefairy is still much easier to find in the games NOW. However it DOES still have a relatively mid-line base capture rate of 150, making it a prime Pokemon to use as an example.
As before, I went into Omega Ruby and caught a Clefairy myself (A level 19 from Meteor Falls) so I could have an accurate HP representation.
No point jumping the gun, let's just try a Pokeball:
mCR = 251.72413793103448275862068965517
Ooh, so close! SO so close in fact that if you had taken it down to 1HP instead you would be GUARANTEED a capture since the mCR is then about 296!
However we DIDN'T take it to 1HP and instead left it with 25% health, so now it's up to chance:
T = 65377.311690431352145162871253246
And chance is VERY MUCH on your side! You've left Clefairy with only about a 1.25% chance of escaping on each shake. You'd have to be REALLY unlucky for the game to pick one of the 159 potential numbers above your threshold on this particular capture... But as I said earlier, it IS still very much possible.
I don't see much point using an Ultra Ball here, or even a Great Ball since you're already so close to perfect odds and it would just be a waste of resources. As such, let's move on to the next example!
Up to now the examples have been showing cases where the second formula is needed. However, certain Pokemon are SO easy to capture that you'll almost never need the second formula at all.
Enter Horsea, with a capture rate of 225. Being only 30 points from the highest possible of potential base capture rates, this one won't put up much of a fight at all.
Coincidentally, the Horsea I caught at level 30 in Omega Ruby on Route 133 had THE SAME max HP as the Clefairy from the previous example, so this will be a PERFECT chance to show how much base capture rate alone will change things!
Even before the math, with a capture rate like that there's no point using anything BUT a Pokeball:
mCR = 377.58620689655172413793103448276
And that's it. Done. There's absolutely no need to go into the second formula. Because the mCR is over 255 the capture is already 100% guaranteed to succeed, and as such the shakes you see are completely superficial. The ONLY reason you're seeing them is because the game's animations have to play out like normal, even though behind the scenes the game isn't calculating a single thing in terms of the capture algorithm.
Fun fact; Going back to Critical Captures, this mCR has about a 148% chance of being a Critical Capture, even though it will literally not help the outcome in any way since the shake checks are rendered moot by the mCR in the first place.
I'm going to throw in two more examples to show the extreme ends of the spectrum; A Ratatta with no damage or status effects and just a Pokeball thrown right away, and then Mewtwo when you throw a Master Ball right away...
Okay, THREE examples, the last one being a Master Ball on the same Rattata, just for fun.
First up, our Rattata (HP based on one I bred and raised to level 5) as if you were a newbie trainer without a care in the world:
mCR = 85
T = 53335.908290744724553212691847968
Remember when you threw a Pokeball at the weakened and sleeping Eevee? The Rattata has less chance to escape than that Eevee, even though you haven't touched it yet. If you so much as bring the Rattata down to HALF-HP you nearly double the capture rate to 179 and bring the shake check up to 61034, and if you took it to 1HP it would have only a 0.67% chance to escape on each shake check.
So now let's try Mewtwo, and this time we'll use the method that MOST people do when capturing Mewtwo; Master Ball on the very first turn.
mCR = 255
Just like I said earlier, EXACTLY 255. Were this Mewtwo broken/hacked, however, and had a capture rate of say 2 instead of 3, the mCR would only come out to 170 meaning that the Master Ball would have a painfully good chance of about 8.4% to fail during each shake check.
But just to prove a point, now comes the Master Ball on that Rattata!
mCR = 21675
Note carefully that's out mCR value, NOT T. That is 8500% of the 255 you need to guarantee a capture. The Rattata has a better chance of destroying the moon than it does of escaping the Master Ball.
I will also add here that there is a FAR more accurate than myself "Capture Calculator" which uses all the same formulas and modifiers I have listed above. It is also simplified to such a point that even the most casual player can use it without worry! I highly recommend it, as I have found it to be stunningly precise in my own experiences.
So there you have it, pretty much every minute detail that goes into capturing a Pokemon... Minus a few little things that I summarized or simplified ahead of time to make it all easier to understand, BUT they're still in there in some form or another!
For everyone who didn't want to read all of that OR just want the liner notes, I'm going to give you a quick-list of the major points made in this post! I plan on doing this for all of these journals, that way you get a simple version each time.
- Every Pokemon species has a base capture rate value assigned to it, the lowest possible number being 3 and the highest being 255.
- The lower the base capture rate, the harder it will be to capture.
- Your chances of capturing a Pokemon increase with three primary factors: How close you get it to 1HP, which ball you use and what status effect you inflict upon it.
- You can use O-Powers to increase your chances even further.
- Your best chances are putting the enemy at 1HP, using a Dusk Ball while it is nighttime OR in a cave and having the enemy asleep (Adding Level 3 Capture O-Power to this has an even greater effect).
- Every capture is determined by at least one mathematical formula but can be subjected to as many as three mathematical formulas.
- The number of times you see a Pokeball shake is based on an RNG check against one of those mathematical formulas, so it is NOT purely random as rumor suggests as you can improve the odds.
- The chance of a Critical Capture is determined by the number of Pokemon you have registered as "Caught" in your Pokedex.
- A Critical Capture forces the game to run only ONE RNG check against a certain formula, as opposed to the usual four.
- According to the math, even with the best possible setup your chances of capturing a Legendary are about 15% per attempt, which is why they're so damn hard to capture.
I hope you enjoyed this journal, and I especially hope you learned something new about just how much goes on every single time you throw a Pokeball... Or at the very least, learned something that you can use the next time you play one of the Pokemon games!
NEXT TIME: Since we just discussed how important certain factors are during capture, I'll be giving you an in-depth guide on how to make a single Pokemon into your one-stop ultimate capture assistant!