A Pokemon randomizer transforms the way you play Pokemon. Instead of facing the same wild Pokemon on the same routes with the same starters every time, a randomizer scrambles everything — wild encounters, starters, trainer teams, moves, abilities, and more. The result is a completely fresh experience every single playthrough.
In this guide, we will cover everything you need to know about the Pokemon ROM randomizer: what it is, how to use it, which games are supported, and how to get the best randomizer settings.
What is a Pokemon Randomizer?
A Pokemon randomizer is a piece of software that takes a Pokemon ROM (the game file) and modifies it according to your selected settings. The most popular tool for this is the Universal Pokemon Randomizer by Dabomstew, which supports nearly every Pokemon game from Generation 1 to Generation 5.
Using a randomizer, you can: randomize starter Pokemon, randomize wild Pokemon encounters, randomize trainer Pokemon (including gym leaders and the Elite Four), randomize Pokemon abilities, moves, and typings, fix trade evolutions so they work without trading, and much more.
Supported Games
The Universal Pokemon Randomizer supports the following games: Pokemon Red, Blue, and Yellow (Gen 1), Pokemon Gold, Silver, and Crystal (Gen 2), Pokemon Ruby, Sapphire, Fire Red, Leaf Green, and Emerald (Gen 3), Pokemon Diamond, Pearl, Platinum, HeartGold, and SoulSilver (Gen 4), Pokemon Black, White, Black 2, and White 2 (Gen 5).
For Gen 6 and beyond (X and Y, Omega Ruby, Alpha Sapphire, Sun and Moon, Sword and Shield, Scarlet and Violet), dedicated randomizer tools are available separately.
How to Use the Pokemon Randomizer
Step 1 – Download the Universal Pokemon Randomizer from the official source. Make sure you have Java installed on your computer.
Step 2 – Open the randomizer application.
Step 3 – Click ‘Open ROM’ and select your Pokemon game ROM file.
Step 4 – Customize your randomizer settings. Popular settings include: Random Starters (choose 3 random Pokemon as starters), Random Wild Pokemon (every route has different wild Pokemon), Random Trainer Pokemon, Fix impossible evolutions (trade evolutions now evolve by level), and Random Abilities.
Step 5 – Click ‘Randomize (Save)’ to save your randomized ROM as a new file.
Step 6 – Load the new ROM in your emulator and enjoy your randomized playthrough.
Pokemon Randomizer by Game
Pokemon Fire Red Randomizer
Pokemon Fire Red is one of the most popular games to randomize. The original Kanto experience with a completely random twist makes for a fantastic playthrough. Use the Universal Pokemon Randomizer with the Gen 3 Fire Red ROM for best results.
Pokemon Emerald Randomizer
Pokemon Emerald randomizer is arguably the most popular randomizer run of all time. Hoenn has a great variety of routes and trainer battles, making the randomized version an incredible challenge. The Pokemon Emerald random number generator also affects wild spawns in very interesting ways.
Pokemon Leaf Green Randomizer
Similar to Fire Red, the Leaf Green randomizer uses the same Gen 3 engine and is fully supported by the Universal Pokemon Randomizer.
Pokemon Soul Silver Randomizer
Randomizing HeartGold and SoulSilver gives the Johto games a completely new lease on life. This is one of the best randomizer experiences due to the large Pokedex and diverse route encounters.
Pokemon Platinum Randomizer
The Pokemon Platinum random Pokemon generator is a fan favorite. Sinnoh’s diverse Pokemon selection and challenging late-game make it a top tier randomizer experience.
Randomizer Settings Guide
Starters – Set to ‘Random (completely)’ for maximum chaos, or ‘Random (basic 3-stage)’ for a more balanced experience.
Wild Pokemon – ‘Area 1-to-1’ mapping keeps the number of species per area consistent. ‘Completely random’ is more chaotic but ensures every Pokemon appears somewhere.
Fix Trade Evolutions – Almost always recommended. This ensures Pokemon like Gengar, Alakazam, and Golem can evolve normally without trading.
Random Abilities – Fun setting that mixes up which abilities each Pokemon has. Can lead to hilarious and broken combinations.
Pokemon Randomizer Online
Prefer not to download software? Several online Pokemon randomizer tools allow you to play a pre-randomized ROM directly in your browser. Our website links to the best Pokemon randomizer online options for each generation.
Frequently Asked Questions – Pokemon Randomizer
Does the Pokemon randomizer work on iOS?
Yes! There are iOS-compatible Pokemon randomizer generator options. You typically need a compatible emulator app and the randomized ROM file to get started.
What is pseudo-RNG in Pokemon?
Pokemon games use a pseudo-random number generator (pseudo-RNG) to determine wild encounters, critical hits, and other random events. Understanding pseudo-RNG is key to shiny hunting and IV breeding.
Can I randomize Gen 6 and newer games?
Yes, though these require different tools from the Universal Randomizer. Dedicated tools exist for Pokemon X and Y randomizer, ORAS randomizer, and Scarlet and Violet randomizer via emulator.