Information guide
How to randomize a list fairly
Learn how Fisher-Yates shuffling, Web Crypto random positions, duplicate entries, sampling without replacement, and draw records affect a random list.
Prepared by TaskReadyTools · Updated 2026-07-10 · Review and correction method
What this guide explains
Understand how to prepare and randomize a list before using a browser-based list randomizer.
- Confirm who is eligible and freeze the source list before randomizing; a fair shuffle cannot repair missing, duplicated, or ineligible entries supplied upstream.
- Fisher-Yates visits the retained items from the end toward the start and swaps each position with a uniformly selected earlier position.
- Web Crypto provides stronger browser randomness than Math.random, while rejection sampling avoids modulo bias when mapping random integers into list positions.
- Removing exact duplicates changes the chance of an item being selected. Keep duplicates only when repeated entries intentionally represent extra chances.
- A browser tool can produce a uniform shuffle, but it does not create an independent witness, tamper-proof source list, or auditable high-stakes draw record.
Sources and further reading
- MDN: Crypto.getRandomValues() — Browser Web Crypto random values and security characteristics.
- MDN: Math.random() — Explains why Math.random is not a cryptographically secure random source.
Next step
Use the matching tool
If the file is ready, open the matching tool and run the check in your browser.
Use List Randomizer: Shuffle a List or Pick Random ItemsFAQ
Does removing duplicates make a draw fairer?
Only when duplicate rows are accidental. If repeated rows intentionally represent multiple entries, removing them changes each participant's chance. Decide the rule before running the draw.
What does sampling without replacement mean?
Once an item is picked, it is not returned to the pool for that result. Picking three items without replacement therefore produces three different retained rows.
Can a browser list randomizer prove a public drawing was honest?
No. It can shuffle the list locally, but it cannot prove the source list was complete or unchanged and does not provide an independently witnessed audit record.