UUID Generator: Create Random UUID v4 Values

  • Free
  • No sign-up
  • Runs in your browser
  • Last updated 2026-10-07
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Generate up to 100 random UUIDs at once and copy them with one click.

Everything you enter is processed in your browser and is never sent to a server.

How to use

  1. Enter how many UUIDs you need, from 1 to 100.
  2. Choose uppercase and whether to keep the hyphens, then press Generate.
  3. Press Copy all to copy the list, one UUID per line.

Examples

Default options
→ xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
The format of a version 4 UUID in lowercase. The 4 is always the version, and y is always 8, 9, a or b. The other characters are random hexadecimal digits.
123e4567-e89b-12d3-a456-426614174000 with Uppercase on
→ 123E4567-E89B-12D3-A456-426614174000
123e4567-e89b-12d3-a456-426614174000 with Hyphens off
→ 123e4567e89b12d3a456426614174000

How it works

Each value comes from the browser function crypto.randomUUID(), which produces a version 4 UUID from the browser’s secure random number generator, as specified in RFC 9562.

Of the 128 bits, 6 are fixed: 4 bits mark the version (4) and 2 bits mark the variant (which is why the first digit of the fourth group is always 8, 9, a or b). The remaining 122 bits are random.

The options only change how the value is written. Uppercase converts the letters, and removing hyphens joins the five groups into one 32-character string. The value itself stays the same.

Sources

Frequently asked questions

What is a UUID?
A UUID (universally unique identifier) is a 128-bit value, usually written as 32 hexadecimal digits in five groups separated by hyphens. It is used as an identifier that can be created anywhere without a central registry.
Can two generated UUIDs be the same?
A version 4 UUID has 122 random bits, so a repeat is extraordinarily unlikely in practice. It is not strictly impossible, so systems that need a guarantee should also enforce uniqueness, for example with a database constraint.
Are these UUIDs safe to use as secrets?
They come from the browser's cryptographically secure random number generator, but a UUID is meant as an identifier, not as a password or token. Use a purpose-built secret generator for credentials.
What does version 4 mean?
Version 4 means the UUID is built from random numbers. Other versions use timestamps or names, and this tool does not generate them.
Are the UUIDs stored or sent anywhere?
No. They are generated in your browser and never leave it.

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