The current maximum is **3000** for Pokémon storage, and **2500** for item storage.

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Originally, it was 1000. As others have also, I fully upgraded mine. I can also confirm that the price stayed the the same for every upgrade purchased to the maximum.

Here is a screenshot of my storage at 1000 each, and the message I got after trying to buy another upgrade once the cap was reached:

[![Your storage is fully upgraded][1]][1] 

Is it worth maxing Pokemon storage? It really does come down to this: for most people, this is NOT necessary. It simply fits the way I wanted to play Pokémon GO. I am not interested in having the highest CP Pokémon or battling Gyms for the time being. I simply enjoy playing "my way", I don't see the value of maxing out Pokémon Storage for 99.999% of players.

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**Updates:**

 * In June 2017, max capacity for items [was increased to 1500][2].
 * In May 2018, max capacity for items [was increased to 2000][3].
 * In July 2019, max capacity for Pokemon [was increased to 2500][4].
 * In November 2019, max capacity [was increased][5] to 3000 for Pokémon and 2500 for items.


  [1]: https://i.sstatic.net/X8gUI.jpg
  [2]: https://twitter.com/PokemonGoApp/status/878038226191233028
  [3]: https://twitter.com/PokemonGoApp/status/996480700877504512
  [4]: https://twitter.com/PokemonGoApp/status/1155908375630295045
  [5]: https://twitter.com/PokemonGoApp/status/1197985622549573633