Free Tool

UUID / GUID Generator

Generate random UUID v4 identifiers instantly — single or bulk generation.

Number of UUIDs

Format:

Click Generate to create UUIDs.

What Is a UUID / GUID?

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit label used in software to uniquely identify information without a central coordinating authority. UUIDs are standardized by RFC 4122 and are represented as 32 hexadecimal digits displayed in five groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

UUID v4 is the most popular variant — it is entirely randomly generated (except for a few version bits), making the probability of collision astronomically small. With 2¹²² possible values, you'd need to generate roughly 1 billion UUIDs per second for about 85 years to have even a 50% chance of a single collision.

How to Use This Tool

Enter a number between 1 and 100 in the count field.
Choose your preferred format: lowercase or UPPERCASE, with or without hyphens.
Click Generate to instantly produce random UUID v4 identifiers.
Click the Copy button on any individual UUID to copy it, or use Copy All to copy the full list.
Use Regenerate to produce a fresh set with the same settings, or Download .txt to save them.

Common Use Cases

Database primary keys — UUIDs are ideal for distributed systems where auto-increment integers cause conflicts.
Session & token IDs — Secure, unguessable identifiers for user sessions or API tokens.
File naming — Prevent file name collisions in cloud storage or CDN uploads.
Microservices — Trace requests across services with a unique correlation ID.
Testing & mock data — Quickly populate test datasets with realistic unique identifiers.
GUIDs in Windows / COM / .NET — Many Microsoft technologies use GUIDs extensively for component registration.

Frequently Asked Questions

What is the difference between UUID and GUID?

They are essentially the same thing. UUID is the open standard term (RFC 4122), while GUID (Globally Unique Identifier) is Microsoft's implementation. Both refer to a 128-bit unique identifier and are fully interchangeable in practice.

Is UUID v4 truly unique?

UUID v4 is randomly generated and provides approximately 5.3 × 10³⁶ possible values. While not mathematically guaranteed to be unique, the probability of collision is so infinitesimally small (roughly 1 in 5.3 undecillion) that it is considered unique for all practical purposes.

Are the UUIDs generated here cryptographically secure?

This tool uses the browser's built-in crypto.getRandomValues() API when available, which provides cryptographically strong random numbers. This meets the requirements for most security-sensitive use cases like session tokens.

What is the difference between UUID with and without hyphens?

Hyphens are part of the standard UUID representation for human readability, grouping the 32 hex characters into five segments (8-4-4-4-12). The "no hyphens" format is a compact 32-character hex string — the same value, just without separators. Many databases and systems accept both formats.

Can I use these UUIDs in production?

Yes. The UUIDs generated are standard RFC 4122 compliant v4 identifiers, identical to those produced by libraries like uuid in Node.js, java.util.UUID, Python's uuid.uuid4(), or C#'s Guid.NewGuid().

What are the other UUID versions?

UUID v1 is time-based (includes a timestamp and MAC address). UUID v3 and v5 are name-based (deterministic, using MD5 or SHA-1 hashing). UUID v4 (this tool) is purely random. UUID v7 is a newer standard combining a timestamp with random data for better database index performance.