View source for Trainer ID number

[[File:USUM status screen.png|thumb|The [[summary]] screen of a {{p|Pikipek}} in [[Generation VII]] with a Trainer ID number of 291177]]
A [[Pokémon Trainer]]'s '''ID number''' (Japanese: '''IDNo.''') is a [[Pseudorandom number generation in Pokémon|randomly generated]] number that is assigned to a player when they create a new save file. Any Pokémon that this Trainer obtains have the number shown in their [[summary]]; it is used, in conjunction with the [[Original Trainer|Trainer's name]] and [[gender]], to identify whether the Pokémon is an [[outsider Pokémon]]. The ID numbers of a player's Pokémon are also used in the [[Pokémon Lottery Corner|Loto-ID]] to determine whether they will win a prize, and if so which prize they will win. Finally, starting in [[Generation III]], whether a Pokémon is {{Shiny}} is determined by a formula that takes into consideration their ID number and [[personality value]].

The smallest possible Trainer ID number is 0. Prior to [[Generation VII]], the largest was {{wp|65535 (number)|65535}}; starting in Generation VII, it is instead 999999. Prior to [[Generation IX]], ID numbers were zero-padded, so if the Trainer ID was less than 5 (Generations {{gen|I}} to {{gen|VI}}) or 6 (Generations {{gen|VII}} and {{gen|VIII}}) digits long, zeroes would be added to the beginning to make it that length.

{{pkmn|Egg}}s use ????? (prior to Generation VII) or ?????? (from Generation VII onwards) as their ID number until they are hatched. [[Shadow Pokémon]] also use ????? as their ID number until they are [[Purification|purified]], at which point the number changes to that of the Trainer who [[Snagging|snagged]] the Pokémon.

==Secret ID==
From [[Generation III]] onward, in addition to their regular ID numbers, Trainers and Pokémon are also assigned a second, unseen ID number different from the visible one. This number exists to reduce the chances of the games erroneously identifying a Pokémon from another Trainer as not being an [[outsider Pokémon]], since even if two Trainers share the exact same name, gender, and Trainer ID number, the games will still recognize their Pokémon as coming from different Trainers should their secret ID numbers be different. A Pokémon's secret ID number is also used along with its main ID number and [[personality value]] in determining if it is {{Shiny}}. Although a secret ID number cannot be viewed without [[Cheating|cheating devices]], it is possible to calculate it.

Secret IDs of Pokémon obtained prior to [[Generation VII]] are five digits long; those of Pokémon obtained in Generation VII onwards are four digits long. Pokémon [[transfer]]red to [[Pokémon Bank]] from the [[Virtual Console]] releases of [[Generation]]s {{Gen|I}} and {{Gen|II}} are given a secret ID of 0.

If two different Trainers have the same [[Original Trainer|Trainer name]] and gender, as well as identical ID numbers and secret ID numbers (a 1 in 4,294,967,296 chance), the games will recognize the two Trainers as the same and will not consider their Pokémon to be [[outsider Pokémon]], which can cause minor bugs related to [[List of locations by index number|met location]]. For example, [[Pokémon Colosseum]] and {{Pokémon XD}} use location index numbers that conflict with each other, so if one player has a Pokémon from the other game yet that Pokémon is not an outsider, it will likely display the wrong met location rather than the fallback "distant land" normally used for outsider Pokémon. Conversely, {{game|Ruby and Sapphire|s}} (not Emerald) and {{game|FireRed and LeafGreen|s}} use location index numbers that are incompatible but do not overlap, so if one player has a Pokémon from the other game that is not an outsider, it will display the otherwise-unreadable text "Met somewhere." rather than the correct "Met in a trade."

==Alterations in Generation VII==
From [[Generation VII]] onward, the Trainer ID is a six-digit number instead of a five-digit number. Instead of generating two 16-bit numbers (between 0 and 65535), one for Trainer ID and one for secret ID, the game instead generates one 32-bit number (between 0 and 4,294,967,295), then takes the last six digits as the Trainer ID. The first four digits then essentially become the secret ID, ranging from 0 to 4294. 

If a Pokémon is [[transfer]]red to Generation VII or later from a previous generation, its Trainer ID and secret ID will both remain 5 digits long.

==Special ID numbers==
{{main|List of notable ID numbers}}
In most cases, Pokémon received from [[in-game trade]]s, [[Event Pokémon|events]], or other such special conditions have a predetermined ID number.

==Loto-ID==
{{main|Pokémon Lottery Corner}}
Once per week in [[Generation II]] and once per day in Generations {{gen|III}}, {{gen|IV}}, {{gen|VI}}, {{gen|VII}}, and {{gen|VIII}}, the player may take part in the Loto-ID. This involves the generation of a random five-digit number, which is compared with the player's Pokémon's ID numbers. Depending on the game and the nature of the matching digits, the player can receive a prize. This feature is not included in the [[Generation I]], [[Generation V]], or [[Generation IX]] games, and is also absent from [[Pokémon Legends: Arceus]].

==Differing events==
Some events in the games differ depending on the player's ID number. These usually utilize the last digit or the number {{wp|modulo operation|modulo}} as the number of variations of the event. As the ID number can't be modified after the creation of a save file, these events are set as soon as a new file is created. These events include:

===Generation II===
* The encounter rate of each [[headbutt tree]]. 

===Generation III===
* Which one of the [[old guys]] will appear in [[Mauville City]].
* Which [[Berry]] the {{tc|Beauty}} will give daily on [[Hoenn Route 120|Route 120]].
* Which [[Pokémon Center Ladies|lady]] will appear in the [[Lilycove City]] [[Pokémon Center]].{{sup/3|E}}
* Which Trainer class will represent the player in a [[Secret Base]] when they mix records.
[[Mixing records]] allows players to exchange events. An online calculator to determine the events based on Trainer ID in Generation III can be found [https://web.archive.org/web/20230702210240/https://pokecheats.net/tools/calculators.php?do=trainer here].

===Generation IV===
* Where two of the four [[Honey Tree]]s that have a chance of containing {{p|Munchlax}} are located.
* Which of two [[Fossil]]s ([[Armor Fossil|Armor]] or [[Skull Fossil|Skull]]) will appear in the [[Underground]].{{sup/4|Pt}}

===Generation V===
* Which shop the first visitor on [[Join Avenue]] will open.{{sup/5|B2W2}}

===Generation VI===
* Which Berry the {{tc|Aroma Lady}} will give daily on [[Hoenn Route 120|Route 120]].{{sup/6|ORAS}}

===Others===
Additionally, some features such as the coloration of [[nickname]]d Pokémon in [[Pokémon Stadium 2]], the password for resetting time in {{game2|Gold|Silver|Crystal}}, [[Walda]]'s wallpapers in {{g|Emerald}}, and [[Primo]]'s gifts are calculated using the player's ID number for their outputs. A password generator, such as the one found in [[filb.de]], is required to determine the inputs to trigger some of these events, while others, such as the rate at which specific {{p|Unown}} forms spawn in {{game|FireRed and LeafGreen|s}} or the two remaining Munchlax Honey Trees, use the secret ID number for their calculations.

==In other languages==
{{langtable|color=ddf|bordercolor=ccf
|zh_yue=ID No.
|zh_cmn=ID No.
|da=ID-nummer
|fr={{tt|Nº|Numéro}} ID
|de=ID-Nummer
|it=ID
|ko=IDNo.
|es={{tt|N.º|Número}} ID<br>Número Identificador{{tt|*|Red & Blue Nintendo 3DS Virtual Console manual}}
|sv=ID-nummer
}}

==External links==
* [https://web.archive.org/web/20230702210240/https://pokecheats.net/tools/calculators.php?do=trainer Trainer ID Event Calculator at pokecheats.net (Archive)]

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{{Project Games notice|game mechanic}}

[[Category:Game mechanics]]
[[Category:Terminology]]

[[de:ID-Nummer]]
[[es:ID de entrenador]]
[[fr:ID]]
[[it:Numero ID Allenatore]]
[[ja:ID]]
[[zh:ID No.]]