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UUID Generator

Generate random v4 and time-ordered v7 UUIDs in bulk, in the format you need. They are created in your browser with a secure random source.

UUID Generator: the tool

0 UUIDs · version 4

Generating…

How to use UUID Generator

  1. Choose the version: v4 for fully random identifiers, or v7 for identifiers that sort by creation time.
  2. Set how many UUIDs you need, from 1 to 1,000.
  3. Adjust the format: uppercase, hyphens and braces change the text without creating new values.
  4. Press Generate for a new batch. Copy the list, or download it as a text file with one UUID per line.

Example

Both samples are valid UUIDs. The first digit of the third group is the version, and the first digit of the fourth group is 8, 9, a or b, which marks the variant defined by RFC 9562.

Version 4 (random)
f47ac10b-58cc-4372-a567-0e02b2c3d479
Version 7 (time-ordered). The first 12 digits, 018f3b5e7c4a, are the timestamp: 2024-05-02 22:13:19.050 UTC
018f3b5e-7c4a-7b3e-9d21-5a6f0c8e4d17

About this tool

A UUID (universally unique identifier) is a 128-bit number written as 32 hexadecimal digits in five groups, 8-4-4-4-12. It lets separate systems create identifiers on their own without coordinating and still avoid clashes. The format is defined in RFC 9562, which replaced RFC 4122 in 2024.

Version 4 fills 122 of the 128 bits with random data. Version 7 starts with a 48-bit Unix timestamp in milliseconds followed by random bits, so values created later sort after earlier ones. That ordering makes version 7 a better primary key for databases, because new rows are appended instead of being scattered through the index. This tool also keeps version 7 values in strict order when many are created in the same millisecond.

Every UUID is generated in your browser with crypto.getRandomValues, the browser's cryptographically secure random source. Nothing is sent to a server and the page does not keep a history.

UUID versions this tool generates

VersionBuilt fromSorts by creation timeGood for
v4Random bitsNoGeneral-purpose identifiers, test data, correlation IDs
v7Timestamp, then random bitsYesDatabase primary keys, event logs, anything read back in order

Frequently asked questions

What is the difference between UUID v4 and v7?

A v4 UUID is random from start to end, so two values tell you nothing about each other. A v7 UUID begins with the creation time, so values sort in the order they were made. Choose v7 when the identifiers are stored in an index or read back in order, and v4 when you want no information in the value.

Can two generated UUIDs be the same?

In practice no. A v4 UUID has 122 random bits, and you would need to generate about 2.7 × 10^18 of them before the chance of a single duplicate reaches 50%. Version 7 values are also unique because they combine a timestamp, a counter and random bits.

Are UUIDs suitable as passwords or secret tokens?

They are built to be unique, not to be secret. Version 4 values come from a secure random source, but version 7 values are partly predictable because they begin with the time. For passwords, session tokens or API keys, use a generator designed for secrets.

Does a v7 UUID reveal when it was created?

Yes. The first 48 bits are the creation time in milliseconds, and anyone holding the UUID can read them. If the creation time of a record must stay private, use v4.

Is a GUID the same as a UUID?

Yes. GUID is the name used in Microsoft products for the same 128-bit identifier. The Uppercase and Braces options produce the {XXXXXXXX-XXXX-...} style often shown by Windows tools.

Are the generated UUIDs stored or sent anywhere?

No. They are created and shown in your browser tab only. Close or reload the page and they are gone.

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