Are these UUIDs really random?

Yes. They're created with your browser's cryptographically secure random number generator (crypto.randomUUID), not Math.random, and never come from a server.

Can two UUIDs ever be the same?

In theory, but practically never. A v4 UUID has 122 random bits. You'd need to generate a billion per second for about 86 years to have a 50% chance of a single collision.

What's the difference between a UUID and a GUID?

Nothing meaningful. GUID is Microsoft's name for the same 128-bit identifier. GUIDs are often written in uppercase and wrapped in braces, which you can switch on here.

You can generate up to 1,000 UUIDs at a time. Press Generate again for another batch.

UUID Generator

Generate one or a thousand secure, random version 4 UUIDs. Copy or download them.

Processed locally

Nothing here yet.

Choose how many you need and press Generate. Fresh UUIDs appear in this list.

Instructions

How to use it

01A fresh UUID is ready as soon as the page loads. Copy it with the button beside it.
02Need more? Set a quantity (up to 1,000) or pick a preset, then press Generate.
03Toggle uppercase, hyphens or braces to match the format your code expects.
04Copy one, Copy all (one per line), or download them as a .txt file.

About

What it does

A UUID (universally unique identifier) is a 128-bit label written as 32 hexadecimal digits, like 3b241101-e2bb-4255-8caf-4136c566a962. UUIDs let systems create IDs independently, without a central counter, and still never clash.

This generator makes version 4 UUIDs as defined in RFC 9562: 122 random bits plus fixed version and variant markers, produced by your browser's cryptographically secure random number generator.

Settings explained

Uppercase: UUIDs are case-insensitive; Microsoft tools often show them in capitals.
Hyphens: Remove them for a compact 32-character form some databases and URLs prefer.
Braces: Wraps each UUID in {curly braces}, the traditional Windows GUID style.

Good for

Primary keys for database rows
Request and correlation IDs in logs
Unique file names for uploads
Test data and fixtures

Questions, answered

Are these UUIDs really random?: Yes. They're created with your browser's cryptographically secure random number generator (crypto.randomUUID), not Math.random, and never come from a server.
Can two UUIDs ever be the same?: In theory, but practically never. A v4 UUID has 122 random bits. You'd need to generate a billion per second for about 86 years to have a 50% chance of a single collision.
What's the difference between a UUID and a GUID?: Nothing meaningful. GUID is Microsoft's name for the same 128-bit identifier. GUIDs are often written in uppercase and wrapped in braces, which you can switch on here.
Is there a limit?: You can generate up to 1,000 UUIDs at a time. Press Generate again for another batch.

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