UUID Generator

Free UUID generator. Create cryptographically-random version 4 UUIDs in bulk with options for uppercase, no hyphens and braces — copy or download. Generated in your browser.

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🔒 Every UUID is generated locally in your browser with cryptographically secure randomness — nothing is sent to a server or logged.

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Free UUID Generator (v4)

This free online UUID generator creates cryptographically random RFC 4122 version 4 UUIDs in bulk — up to 1,000 at a time. Choose uppercase, strip the hyphens, or wrap each value in braces, then copy the whole list or download it as a .txt file. It’s free, instant and runs entirely in your browser, so no identifier you create is ever sent to a server.

How to use the UUID generator

  1. Enter how many UUIDs you need (between 1 and 1,000).
  2. Tick any options you want: Uppercase, Remove hyphens or Wrap in braces.
  3. Click Generate — a fresh set of random UUIDs appears instantly.
  4. Use Copy all to copy the list, or Download .txt to save it as a file.

What is a UUID / GUID?

A UUID (Universally Unique Identifier), also called a GUID on Microsoft platforms, is a 128-bit value written as 32 hexadecimal digits in the familiar 8-4-4-4-12 pattern, for example 3f2504e0-4f89-41d3-9a0c-0305e82c3301. Its job is to be unique without any central authority handing out numbers — any machine can mint one independently and trust that it will not clash with identifiers created elsewhere.

A version 4 UUID is built almost entirely from random bits: 122 of the 128 bits come from a random source, with the remaining bits fixed to mark the version (the 4) and the variant. Because there are about 5.3 × 1036 possible v4 values, the chance of two randomly generated UUIDs colliding is so small it is treated as negligible in practice. This generator draws its randomness from your browser’s secure crypto API rather than a predictable pseudo-random function, which makes the output suitable for real-world use. Common uses include primary keys in databases, distributed system identifiers, file and object names, idempotency keys for safely retrying API requests, session tokens and message IDs.

Frequently asked questions

Are these UUIDs truly random and safe to use?
Yes. Each UUID is generated in your browser using the cryptographically secure crypto.getRandomValues / crypto.randomUUID API, not a weak pseudo-random function. That makes them suitable for database keys, idempotency keys and other production uses.
What is a version 4 UUID?
A version 4 UUID is a 128-bit identifier built mostly from random bits, with a few bits fixed to mark the version and variant. You can spot it by the 4 at the start of the third group, as in xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx.
Can two generated UUIDs ever be the same?
In theory yes, but the probability is so tiny it is treated as negligible. There are over 5 × 1036 possible v4 UUIDs, so even after generating billions you are extraordinarily unlikely to ever see a duplicate.
How many UUIDs can I generate at once?
You can generate between 1 and 1,000 UUIDs per click. If you enter a number outside that range or leave the box blank, it is automatically clamped to a valid value so the tool never breaks.
What is the difference between a UUID and a GUID?
There is essentially no difference. GUID is Microsoft’s name for the same 128-bit identifier; UUID is the term used by the RFC standard. They describe the same format, and the values from this tool work anywhere a GUID is expected.
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