How can I generate UUIDs online for free?

Click Generate on the UUID Generator to create a version 4 UUID instantly — or generate up to 500 at once for bulk needs. IDs come from the browser's crypto.randomUUID, so they're cryptographically secure, and you can copy them in standard, uppercase, or brace-wrapped formats.

What is the difference between UUID and GUID?

Almost nothing in practice. GUID is Microsoft term for the same 128-bit identifier format. A version 4 UUID works fine wherever a GUID is expected.

When should I use the no-hyphens format?

Some systems (certain databases, compact tokens, URL slugs) want the 32 hex characters without dashes. The value is identical; only the presentation differs.

Can two generated UUIDs collide?

Theoretically yes, practically no: with 122 random bits, you would need to generate billions per second for a century to reach even a tiny collision chance.

DEVELOPER TOOLS · FREE ONLINE TOOL

UUID Generator

Bulk-generate cryptographically random version 4 UUIDsTest data, database seeds, API keys, and distributed systems all need unique identifiers without a central counter handing out the next number. This generator produces version 4 UUIDs with 122 bits of cryptographic randomness, from 1 to 100 at a time.

✓ Free to use✓ No sign-up✓ Ready in your browser

// UUID GENERATOR · GET STARTED

Use UUID Generator

Bulk-generate cryptographically random version 4 UUIDs

How many (1-100)

Format

// UUID GENERATOR · HOW IT WORKS

How to use the UUID Generator

Pick count and format

Choose how many UUIDs you need (1 to 100) and a format.

Generate

Click "Generate UUIDs".

Copy results

Copy individual UUIDs or copy them all at once.

// UUID GENERATOR · ABOUT THIS TOOL

About the UUID Generator

Test data, database seeds, API keys and distributed systems all need unique identifiers that do not require a central counter. Version 4 UUIDs solve this with 122 bits of randomness, produced here with the browser cryptographic generator.

Generate up to 100 at a time in the format your system expects: standard lowercase, uppercase, hyphenless or braced. Everything happens locally, so there is no round trip and no logging.

Where it helps most

Unique IDs without coordination.

Database primary keys

Keys that stay unique across shards with no coordination, the standard answer where systems must agree on uniqueness without talking.

Idempotency keys

Idempotency keys let an API safely retry a payment request without double-charging. Each attempt carries a unique key, so retries are safe by construction.

Distributed tracing

Correlation IDs get stamped on every log line of a distributed trace, tying one request's whole journey together across services that never coordinate directly.

Test fixtures

Test fixtures and database seeds need realistic unique identifiers by the dozen. Generate up to 100 at once, then copy individual values or the whole batch.

Formats and facts

One value, four wrappings, zero collisions.

Four formats, one value

Standard lowercase hyphenated suits most databases and APIs. Uppercase fits Windows-world conventions, hyphenless 32-character strings work for compact tokens, and braced form matches config files.

Collisions are not a concern

With 122 random bits, you would need to generate billions of UUIDs per second for a century to reach even a tiny collision chance. The math is genuinely reassuring.

Secure randomness

Values come from the browser's cryptographic random source, the same generator operating systems use for security-sensitive randomness. Nothing predictable, nothing repeated, ever.

UUID Generator: private by design

Everything happens locally in your browser: no round trip, no logging, no waiting.

// UUID GENERATOR · COMMON QUESTIONS

UUID Generator FAQs

What is a UUID?

A UUID, universally unique identifier, is a 128-bit label like 550e8400-e29b-41d4-a716-446655440000. Version 4 UUIDs are randomly generated, making collisions practically impossible, which is why databases and APIs use them as identifiers.

Are these UUIDs really version 4?

What is the difference between a UUID and a GUID?

When should I use the hyphenless format?

Could two generated UUIDs ever collide?

How many UUIDs can I generate at once?

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