UUID Generator (v4)
Generate random version 4 UUIDs with your browser’s secure random number generator. Create up to 100 at once, in lowercase or uppercase, with or without hyphens.
Runs in your browser. Your data is not uploaded.How our tools work
Created on your device with the browser’s secure random number generator. With 122 random bits, a repeat is astronomically unlikely, though not mathematically impossible.
How do I generate a UUID?
Select Generate to create a random version 4 UUID, such as 550e8400-e29b-41d4-a716-446655440000, or set a number to make up to 100 at once. UUIDs are created in your browser with its cryptographically secure random number generator, never Math.random. Choose uppercase, no hyphens or braces, then copy them.
Want to know how UUIDs are structured, or whether to use one instead of a numeric ID? Read our guide: What Is a UUID? Versions, Uniqueness and When to Use One
Key features
Version 4, standard format
122 random bits with the version and variant set as the standard requires, in the usual 8-4-4-4-12 layout.
Secure randomness
Uses crypto.randomUUID() or crypto.getRandomValues(), the browser’s cryptographic generator. Math.random is never used.
Up to 100 at once
Generate a batch and copy them all, one per line.
Formats
Lowercase or uppercase, with or without hyphens, and with or without braces for Windows GUIDs.
Common uses
- Generate unique names for files, records or API requests (not secret tokens)
- Make GUIDs for Windows or .NET projects
Where a UUID is the wrong tool
A UUID identifies something; it isn’t a secret. RFC 9562 says UUIDs should not be used as security capabilities, so don’t use one as a password-reset token, an API key or a session id just because it looks random: identifiers end up in logs, URLs and error reports. Use a token made for the purpose instead.
Version 4 UUIDs don’t sort by time, so a database table keyed by them fills its index in random order. For keys that should sort by creation time, RFC 9562 defines version 7, which puts a timestamp in the first 48 bits. This tool generates version 4 only.
Frequently Asked Questions
What is a UUID?
A universally unique identifier: a 128-bit value written as 32 hexadecimal digits, such as 550e8400-e29b-41d4-a716-446655440000. GUID is Microsoft’s name for the same thing.
Can two UUIDs be the same?
In theory, yes, but a version 4 UUID has 122 random bits, so the chance of a repeat is astronomically small, even across billions of IDs.
What does version 4 mean?
The UUID is made from random numbers. The 13th digit is always 4, and the 17th is 8, 9, a or b.
Sources
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