Developer
UUID Generator
Cryptographically random UUID v4 / GUID values, one at a time or in bulk — generated entirely on your device.
0 UUIDs
Generated with crypto.randomUUID() — cryptographically random, version 4 UUIDs (RFC 4122), created entirely in your browser.
Generate one UUID or a thousand at once, using the browser's native crypto.randomUUID() — a cryptographically secure random number generator, not the weaker Math.random(). Every result is a standard, RFC 4122 version-4 UUID (interchangeable with what Windows calls a GUID), with 122 bits of randomness — enough that collisions aren't a realistic concern even at huge scale. Toggle hyphens and uppercase formatting to match whatever system you're feeding the value into, generate a batch for seeding test data, and copy a single value or the whole list at once. Since generation doesn't depend on any input, there's nothing to upload — it all happens locally.
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How to Use
- 1
A UUID is generated automatically as soon as the page loads.
- 2
Set a count (or click a quick-pick button) and click Generate for one value or a whole batch.
- 3
Toggle Hyphens and Uppercase to match the format you need.
- 4
Click Copy (or Copy all for a batch) to grab the result.
Frequently Asked Questions
How random are these UUIDs?
Each one is generated with the browser's native crypto.randomUUID(), which is built on a cryptographically secure random number generator (CSPRNG) — the same class of randomness used for encryption keys — not Math.random(), which isn't safe for anything security-sensitive.
What's the difference between UUID and GUID?
They're effectively the same thing. UUID (Universally Unique Identifier) is the standard's name (RFC 4122); GUID (Globally Unique Identifier) is Microsoft's term for the same 128-bit format. This tool generates standard version-4 (random) UUIDs, which work as GUIDs anywhere one is expected.
How likely is a collision?
A version-4 UUID has 122 random bits, giving roughly 5.3 x 10^36 possible values. You could generate a billion UUIDs a second for about a hundred years and still have a negligible chance of ever generating the same one twice — collisions are not a practical concern.
Can I generate more than one at a time?
Yes — set the count to any number up to 1000 (or use one of the quick-pick buttons) and click Generate to get that many at once, one per line, ready to copy in bulk for seeding a database or test fixtures.
Is anything sent to a server?
No — every UUID is generated locally in your browser. There's nothing to upload in the first place, since generation doesn't depend on any input from you.