As we technique Pokémon GO’s third anniversary, numerous travelers are still chasing their Youngster and also Fisherman medals. This objectives focus on the height and also weight the wild Pokémon – a part of every Pokémon’s distinct identity that has no various other known result in-game hence far.

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While pondering these Pokémon characteristics many month ago, the Silph research Group collection out to uncover how Pokémon height and weight space determined.

After weighing and measuring nearly 50,000 Pokémon in a massive study, we uncovered workings behind the height and also weight system. This straightforward but elegant design explains:

How height and weight space generatedHow the 2 values are interlinkedHow castle persist across evolutionsThe mechanics behind Pokémon size appraisalsThe odds of receiving a small Rattata or large Magikarp

Due come the modern launch of number of exciting new features (like PvP, the weather system, community Days, and also a complete year that events), this findings were never ever published. Fortunately, this discovery will finally see the light of day! We’re proud to be able to say that the efforts of dedicated Silph researcher both new and old will result in one more entry right into the ever-growing canon of addressed mysteries the Pokémon GO. Without any kind of further hold-up – let’s dive in!

The Data

The data for this study was gathered in 4 segments:

1>2,000MagikarpExplore height and weight in relation to various other Pokémon attributesHeight and also weight
227,000Common PokémonSpeed up data gathering
310,000Species with mean elevation ≥ 1.5 mInvestigate just how rounding affects distribution
48,500Special casesNarrow down specific appraisal boundariesFull appraisal

As the 3rd and 4th segment only clarified results from the previously data sets, an exception was make to enable historical data native January 2017 forward. Data native 2016 was excluded come ensure the results weren’t biased by the beforehand evolution bug¹.

Generating Height and also Weight

With this dataset, Silph researchers were able to turning back engineer the an approach used to generate height and also weight. Starting with the simplest feasible distribution (uniform in between two values) the data was checked to watch if it fit a variety of possible distributions. Each version was rubbish if it no fit the data. This process was repeated several times till the covert methodology provided to create a Pokémon’s height and weight to be uncovered.


A couple of simple steps identify the height of a Pokémon.

Next, random elevation is multiply by the elevation value listed in the Pokémon’s Pokédex entry (or an ext specifically the game master file, which includes full, unrounded values) in bespeak to acquire the final height of the Pokémon. Straightforward as that!Weight

Determining the weight variable requires a pair extra steps. The first step in generating weight is identical to generating height. A arbitrarily number is attracted from a normal circulation with a average of 1 and also a traditional deviation that 1/8. We contact this number random weight. Next, random weight is multiplied by random height squared to obtain an intermediate variable. Let’s call this variable intermediate weight. Mathematically this watch like:

intermediate weight = random load * arbitrarily height2

Finally, intermediate weight is multiplied by the load value listed in the Pokédex (or game master file) to gain the last weight the the Pokémon.


Generating the load in this means has a couple of various effects. First, the load of a Pokémon is much more variable 보다 its height. In fact, it has actually a standard deviation practically 2.8 times that of height. This is why more Pokémon have actually an XS or XL shown on your weight in the Pokémon appraisal screen than height. Secondly, because the random height variable is supplied to calculation the final weight the the Pokémon, the height and also weight the a Pokémon room well-correlated. Friend wouldn’t want a Snorlax that is in the top 1% that height, however the bottom 1% of weight! This algorithm keeps the from happening, but also provides some nice variability.

Here’s a plot to help visualize this relationship. The height and also weight of every Pokémon have been normalized by its mean types height and weight in bespeak to appropriately compare them. This is essentially a plot of the random height and also intermediate weight variables.


Normalized height and weight distribution for all Pokémon species

Evolutions and Rounding

Now the we’ve laid out a an easy framework because that generating height and weight, predicting the brand-new values after ~ evolving her Pokémon is easy. Just divide the height and also weight values presented in the Pokémon appraisal display by the average values displayed in the Pokédex entry for that species, and then main point by the new mean because that the advanced form. We have the right to do this because the arbitrarily height and random weight worths don’t adjust when a Pokémon is evolved.

Now, if you to be to actually try this ~ above a Pokémon, you might find that the values don’t enhance perfectly. This is because of rounding errors. Us were maybe to present this many thanks to a really lucky triplet of similar Pidgeys (nicknamed Harpo, Groucho, and also Chico), provided to united state by Silph Scientist Constituent (DonLothario). Here are your height and weight worths before and also after evolution.

Harpo0.29 m / 2 kg1.06 m / 33.39 kg1.44 m / 43.97 kg
Groucho0.29 m / 2 kg1.06 m / 33.36 kg1.45 m / 43.93 kg
Chico0.29 m / 2 kg1.05 m / 33.4 kg1.43 m / 43.97 kg

For this script to be true, each of the Pidgey’s elevation values need to be saved to a higher degree of accuracy than presented on the appraisal screen. The save weight need to be in between 1.995 kg and 2.005 kg when the elevation is in between 0.285 m and 0.295 m.


Knowing that shown values are rounded is helpful for the last part of the research that investigated the borders of the appraisal system. There are three elevation appraisals which room either presented on screen or have the right to be checked via the appraisal function. Castle are:

The XS and also XL presented next come a Pokémon’s height.The XS and also XL shown next to a Pokémon’s weight.The dimension appraisal provided by your team leader.

The XL and XS shown next to a Pokémon’s elevation or load on that information display are determined by the deviation indigenous the mean height or weight of the species. Anything more than 2 conventional deviations above the mean height or load is XL, and also anything much less than 2 standard deviations listed below the mean height or weight is XS.

However, the dimension appraisal from your team leader is various from the XS and also XL tags. It have the right to be suspect by adding together the random height and also intermediate weight variables discussed previously. We have the right to then to compare this value to the borders shown in the table below.

Possible appraisalsSum of random height and also intermediate weight
Tinier or the tiniest or therefore tinyLess 보다 1.5
Below average in dimension or a little small or rather cuteBetween 1.5 and 1.75
Above typical in dimension or large one or rather sizeableBetween 2.25 and 2.5
 Colossal or just huge or giganticGreater 보다 2.5

All of this is finest illustrated in a graph again.


Appraisal boundaries added to the distribution of height and weight

The XS and also XL markings displayed on a Pokémon’s information display are represented as horizontal or vertical lines in the plot on the left. Interestingly, since of rounding, over there are numerous height and also weight values of specific Pokémon species that can display screen the precise same height/weight ~ above their info page, but differ in their XS or XL symbol indigenous one another. The dimension appraisals from every of the team leaders are diagonal lines shown in the best plot.

Overlaying this boundaries, we can see that several combinations room possible. For example, a Pokémon might be colossal however not XL. You have the right to also clearly see that the XL and XS room far much more common because that weight 보다 height.


All size appraisals in Pokémon go overlaid ~ above one graph

Fisherman and also Youngster Medals

Finally, we would certainly be remiss if we left out the Fisherman and Youngster medal borders from a conversation on height and weight! These borders are found at about 2.5 conventional deviations far from the mean. This equates to a “tiny Rattata” being any type of that room lighter 보다 2.41 kg and a “large Magikarp” being any type of that space heavier 보다 13.13 kg. This values have actually been report by other travelers ~ above The Silph Road, and our data confirms them. Simulating 10,000,000 height and weight worths in R based on the algorithm explained above, us were able to determine that the probability for obtaining a tiny Rattata³ is 11.7% and for large Magikarp that 14.6%. These limits are displayed in the number below:


Parting Words

We hope the you’ve took pleasure in this emergence behind the curtain of the height and weight device of Pokémon GO! together of now, height and also weight don’t affect your Pokémon’s fight readiness or movesets, but simply administer a more realistic backdrop for the game. Hopefully, this article helps friend to determine if you’ve recorded yourself a once-in-a-lifetime Pokémon. We’ll view you on the road, travelers!

Notable Researchers

The Silph Research group would choose to provide a special shoutout to longtime Scientist, DrThod who single-handedly cracked the formula behind Height and Weight. Without his tough work, every these discoveries would not have actually been possible.


¹ In the at an early stage days the Pokémon go it seemed that virtually all Pokémon that were progressed turned the end to it is in XS in weight. This was a pest in the calculation of new weight and height ~ the evolution. It seems that Niantic used the mean elevation of the evolved species and the average weight of the unevolved kind when calculating the new evolved values. All early on Eeveelutions, therefore, appear to be XS with values outside our plot while part Pokémon favor Venomoth turned out XL together their pre-evolution species was heavier.

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² based on our data, a normal circulation was the ideal fitting and also most parsimonious distribution based upon the Akaike info Criterion. However, there was an interesting case that surfaced throughout the July community Day wherein a traveler regulated to capture a Squirtle weighing 0.01kg. Making use of simulations in R, Silph scientists tried to reproduce the aforementioned Squirtle using the regular distribution and the transformation outlined above but were unsuccessful in end 500,000,000 trials. This may show that the distribution for weight has actually slightly heavier tails 보다 a traditional normal circulation (e.g. T-distribution), yet the present dataset can not validate this hypothesis.

³ Alolan Rattata has actually a slightly higher average weight, however the compelled weight of 2.41 remains consistent for one of two people form. This method that the Alolan kind is much less likely 보다 its counterpart to it is in “tiny.”