User Guide
Step 1 — Set the count
- Choose how many UUIDs you need (up to 500).
Step 2 — Pick a format
- Lowercase, uppercase, or braced; with or without hyphens.
Step 3 — Generate
- Press Generate; the UUIDs appear instantly, one per line.
Step 4 — Use them
- Copy all or download as a .txt file. Everything stays in your browser.
About the UUID Generator
This tool creates version-4 UUIDs — universally unique identifiers — in your browser, individually or in bulk. UUIDs are the standard way to label something uniquely without a central authority handing out numbers, which makes them indispensable in software.
What a UUID is
A UUID is a 128-bit value, usually written as 32 hexadecimal digits in five hyphen-separated groups, such as 550e8400-e29b-41d4-a716-446655440000. Version 4 means almost all of those bits are random. Because the space of possible values is so enormous, two independently generated version-4 UUIDs are astronomically unlikely to ever collide, which is exactly what you want for an identifier that has to be unique without coordination.
Where they are used
Developers reach for UUIDs constantly: as primary keys in databases where rows are created across many servers, as request or transaction IDs in logs and APIs, as filenames for uploads, as session tokens, and anywhere two systems need to agree on a unique label without talking to each other first. Generating a batch here is handy for seeding test data, pre-allocating identifiers, or grabbing a single one for a quick task.
Formats
The canonical form is lowercase with hyphens, but other conventions exist. Uppercase is sometimes required by older systems; braces around the value are a Microsoft convention; and stripping the hyphens gives a compact 32-character string that some databases and URLs prefer. The options here let you produce whichever your target expects.
Privacy
The UUIDs are generated entirely in your browser using the secure random source built into modern browsers, so nothing is uploaded. To hash text or compare two pieces of text, see the Hash Generator and Text Diff Checker.
Frequently Asked Questions
What kind of UUID does this generate?
Version 4 UUIDs, which are random. They are the most common type, used for database keys, request IDs, and unique identifiers where you do not need ordering.
How unique are they?
Practically unique. A version-4 UUID has 122 random bits, so the chance of a collision is vanishingly small even across billions of values.
Can I generate many at once?
Yes, up to 500 at a time. Each is on its own line so you can copy the whole block or download it as a text file.
What do the format options do?
You can switch to uppercase, wrap each UUID in braces (a common format on Windows), or remove the hyphens for a compact 32-character form.
Are the UUIDs generated privately?
Yes. They are created in your browser using the built-in cryptographic random generator and never sent anywhere.