Free Online UUID Generator

Generate cryptographically random UUID v4 values - runs entirely in your browser, nothing is sent to a server.

Results are provided for informational purposes only and may contain errors. Please verify important information independently. Use of this tool is at your own risk.

What the UUID Generator does

The UUID Generator creates random version 4 UUIDs such as 3f2b8c1e-9d4a-4f6b-a2c7-5e8d1b0f9a34. Choose how many you need, from 1 to 100 (5 by default), press Generate and copy them, one per line. The IDs are created with crypto.randomUUID(), the browser's built-in, cryptographically secure generator, and never leave your device.

A version 4 UUID is 128 bits long; 122 of those bits are random, and the rest mark the version (the 4 at the start of the third group) and the variant (8, 9, a or b at the start of the fourth group). There are about 5.3 × 10^36 possible values, so the chance of two generated IDs colliding is negligible even across billions of records.

When to use it

  • Creating primary keys for database rows that are generated on the client or across several servers.
  • Producing idempotency keys or correlation IDs for API requests and logs.
  • Filling test fixtures and seed data with realistic IDs.
  • Naming uploaded files so that names never clash.

Worked example

Input

Count: 3

Output

3f2b8c1e-9d4a-4f6b-a2c7-5e8d1b0f9a34
c9e07a52-1b3f-4d8e-9f60-7a2d4c8b1e53
5a8d2f71-e4c9-4b06-8d3a-f1c7e9b2a604

Common questions about the UUID Generator

Are UUIDs really unique?

In practice, yes. With 122 random bits you would need to generate about a billion UUIDs every second for decades before a collision became likely.

UUID or GUID: what is the difference?

None in practice. GUID is Microsoft's name for the same 128-bit identifier. Some Microsoft tools show GUIDs in uppercase or wrapped in braces, but the values are interchangeable.

Are v4 UUIDs good database keys?

They work well, but random values scatter inserts across a B-tree index. For very large tables, time-ordered UUID version 7 keeps new rows together and is often faster.

Can I use a UUID as a secret token?

A v4 UUID from crypto.randomUUID() is unpredictable, but its format is recognisable and fixed. For API keys and secrets, the Random String Generator lets you choose a longer length and alphabet.

Is this tool free?

Yes, it's free to use. No signup, no email required. Get results on this page.

How do I get my result?

Use the tool on this page. Your result appears here; no email delivery is required.