UUID Generator

About the UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), sometimes called a GUID, is a 128-bit value written as 32 hexadecimal characters in five groups, like 3f2504e0-4f89-41d3-9a0c-0305e82c3301. Its whole point is uniqueness: generate one anywhere, any time, and the odds of it ever colliding with another are effectively zero — so you don't need a central authority to hand out IDs.

This generator uses your browser's cryptographically secure random source, so the IDs are genuinely unpredictable. Make one or hundreds at a time, format them however your project needs, and copy or download the lot — nothing is sent to a server.

Which version should I use?

• v4 (random) is the default and the right choice almost always — 122 bits of pure randomness, ideal for database keys, tokens and general-purpose IDs.
• v7 (time-ordered) starts with a millisecond timestamp, so the IDs sort in the order they were created. That makes them database-index-friendly while still being random. Use it when ordering or insert performance matters.
• nil is the special all-zero UUID (00000000-0000-0000-0000-000000000000), used as a placeholder or "no value".

Formatting options

• Hyphens: keep the standard dashed form, or turn them off for a compact 32-character string.
• Uppercase: switch the hex digits to capitals (some systems, like parts of Windows, prefer this).
• Braces: wrap each ID in { }, the classic Microsoft GUID style.

Common Use Cases

• Database keys: unique primary keys that don't leak record counts.
• API tokens & request IDs: trace requests across services.
• File & session names: avoid collisions without coordination.
• Test data: generate batches of realistic identifiers.

Need random numbers or strings instead? Try the Random Number & String Generator. Building secure secrets? See the Password Generator.

Frequently Asked Questions

Are these UUIDs really unique?

For practical purposes, yes. A version 4 UUID has 122 random bits, so you'd have to generate billions of them before a collision became even remotely likely. They're generated with a cryptographically secure random source.

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 shown in uppercase and wrapped in braces, which you can toggle here.

When should I pick v7 over v4?

Choose v7 when you want the IDs to sort chronologically — for example as a database primary key, where time-ordered values keep the index tidy and inserts fast. Otherwise v4 is the simplest, safest default.

How many can I generate at once?

Up to 500 per batch. Set the count, hit Generate, then copy them all or download them as a text file.

Is anything sent to a server?

No. Every UUID is generated locally in your browser, so nothing is transmitted or stored anywhere.