A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information. Standard format: 8-4-4-4-12 hex characters like 550e8400-e29b-41d4-a716-446655440000.

Version 4 UUIDs are randomly generated using cryptographically secure random numbers. Other versions use time-based or name-based generation.

Can two UUIDs ever be the same?

The probability of collision is astronomically small — about 1 in 2^122. For practical purposes, v4 UUIDs are statistically unique.

Is a GUID the same as a UUID?

Yes — GUID (Globally Unique Identifier, used by Microsoft) and UUID refer to the same standard format (RFC 4122).

UUID Generator — Generate v4 UUIDs Online

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value represented as 32 hexadecimal characters grouped as 8-4-4-4-12. Version 4 UUIDs use cryptographically secure random bits, making them statistically unique across all systems and time.

Example: 550e8400-e29b-41d4-a716-446655440000

Output Formats

Lowercase

550e8400-e29b-41d4-a716-446655440000

UPPERCASE

550E8400-E29B-41D4-A716-446655440000

No dashes

550e8400e29b41d4a716446655440000

Braces

{550e8400-e29b-41d4-a716-446655440000}

How to Use It

Open the tool

Go to Encode / Decode and scroll to the UUID Generator.

Choose format

Select lowercase, UPPERCASE, no-dashes or {braces} depending on where you'll use the UUID.

Set quantity

Choose how many UUIDs to generate — from 1 to hundreds at once.

Generate and copy

Click Generate and copy the UUIDs with one click.

Pro Tips

💡Use UUIDs as database primary keys to avoid ID enumeration attacks — sequential integer IDs reveal how many records exist.

💡The no-dashes format is 32 characters — useful when you need a compact identifier and the receiving system doesn't require dashes.

💡In JavaScript: crypto.randomUUID() generates a v4 UUID natively in modern browsers and Node.js 15+.

💡Generate a large batch at once (50–100) if you need UUIDs for seed data or test fixtures — copy them all in one go.

Frequently Asked Questions

What is a UUID?

A 128-bit Universally Unique Identifier represented as 32 hexadecimal characters in 8-4-4-4-12 format. v4 UUIDs are randomly generated.

Can two generated UUIDs be the same?

The probability is approximately 1 in 2^122 — astronomically small. For all practical purposes, v4 UUIDs are unique.

What's the difference between UUID and GUID?

They are the same thing. GUID (Globally Unique Identifier) is Microsoft's name for the same RFC 4122 standard format.

What does v4 mean?

Version 4 UUIDs are randomly generated. Other versions: v1 is time-based, v3 and v5 are name-based hashes.

Generate UUIDs now

Open the UUID Generator and create as many v4 UUIDs as you need — free, instant, no login.

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