A visual explanation of Fisher–Yates shuffle

In plain words

This interactive visualization explains the Fisher–Yates shuffle algorithm, a method for randomizing the order of elements in a deck or list. It demonstrates how repeatedly selecting a random card from the remaining deck and setting it aside creates an unbiased shuffle, ensuring fair card games like Texas Hold 'em. The tool shows the algorithm's mechanics through visual diagrams, helping developers and others understand how to implement proper randomization in code without introducing bias.

written from the facts on this page · September 2026

From the sources

If you want to play a game of Texas Hold ‘em with friends, you should shuffle the deck first to randomize the order and insure a fair game. But how? A quick way of seeing an algorithm’s bias is a matrix diagram . A simple but effective way of doing this is to pull a random card from the deck repeatedly and set it aside, incrementally building a new stack. As long as you pick each remaining card from the deck with equal probability, you’ll have a perfectly-unbiased random stack when you’re done: But let’s say instead of a physical deck of cards, you wanted to write code to perform this same task with an in-memory array of n elements. Sounds straightforward (in part), but how would you pick a…from bost.ocks.org

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