CraftTools

UUID & Random Number Generator

Guide: How to Create a Strong Password (and Keep It Safe)

Nothing you enter or choose here leaves your device. This tool runs in your browser.

How to use

  1. 1Choose UUID or Random numbers.
  2. 2For UUIDs, pick a version and how many. For numbers, set a minimum, maximum and how many.
  3. 3Turn on "No repeats" if every random number must be different.
  4. 4Click Copy to copy the results.

Frequently asked questions

What is the difference between UUID v4 and v7?

Version 4 is completely random. Version 7 starts with a timestamp, so UUIDs sort by creation time, which is friendlier to database indexes.

Can two UUIDs be the same?

In practice no. A random UUID has 122 random bits, so the chance of a collision is astronomically small.

Are the random numbers really random?

They come from your browser's cryptographically secure random generator, the same source used for the password generator, with no bias between values.

Can I use these for passwords or tokens?

UUIDs identify things and aren't meant to be secret. For passwords use the password generator.

Read the guides

Learn how this works and how to get the most from it.

Security

How to Create a Strong Password (and Keep It Safe)

Why length beats complexity, how long a password should be, how passphrases work and how developers should store passwords.

2 min read

Developer

UUID, ULID and NanoID: Which Unique ID Should You Use?

How UUID v4, UUID v7, ULID and NanoID differ, why sortable IDs help databases, and how to pick the right one for your project.

1 min read

Developer

How Random Number Generators Work and Why Fair Picks Matter

The difference between ordinary and secure randomness, how to pick fairly without repeats, and what dice and coins really do.

2 min read

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