A UUID (Universally Unique Identifier) is a 128-bit label standardized by RFC 4122, represented as a 32-character hexadecimal string divided into five groups by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). A UUID generator produces these identifiers for use as unique keys in databases, APIs, and distributed systems.

What is the difference between a UUID and a GUID?

UUID and GUID (Globally Unique Identifier) refer to the same concept — Microsoft coined the term GUID for its implementation of the UUID standard. Both follow the same format and can be generated by the same UUID generator; the terms are interchangeable in practice.

When should I use UUIDs?

Use a UUID generator when you need identifiers that are unique across distributed systems without requiring a central coordinator. Common use cases include database primary keys, session tokens, file names for uploads, message IDs in event queues, and any scenario where sequential integer IDs would expose enumeration risks.

What are the different UUID versions?

UUID v1 is time-based and includes the generating machine's MAC address. UUID v3 and v5 are deterministic, derived from a namespace and name using MD5 or SHA-1 hashing. UUID v4, which this UUID generator produces, is purely random and is by far the most widely used version for general-purpose unique identifiers.

Can two UUIDs ever be the same?

In theory yes, but in practice the probability is astronomically small. A UUID v4 generator draws from a space of 2^122 possible values, making the chance of a collision negligible even when generating billions of IDs. For the vast majority of applications, UUIDs can be treated as globally unique without any additional coordination.

UUID Generator — Free Online UUID/GUID Tool

UUID Generator

Generate random UUIDs (v4) instantly. Bulk generate, validate, and copy.

Processed locally in your browser

Generate cryptographically secure UUID v4 identifiers instantly with this free online UUID generator.

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How to Use

Generate cryptographically secure UUID v4 identifiers instantly with this free online UUID generator.

Click Generate. A new random UUID appears immediately, ready to copy. Each UUID is generated using the browser's crypto.getRandomValues API for true randomness.
Customize the format. Toggle between uppercase and lowercase, and choose whether to include hyphens. Some systems require a specific format — adjust as needed.
Bulk generate. Set the quantity (up to 100) and click Generate to create multiple UUIDs at once. The full list is displayed and can be copied with a single click.
Validate a UUID. Paste an existing UUID into the validator to check whether it conforms to the standard format and identify its version.
Copy the result. Click the copy button next to any UUID to send it to your clipboard for use in your database, API, or configuration.

UUIDs are the standard way to create unique identifiers in distributed systems without a central coordinator. This generator runs entirely in your browser — no IDs are transmitted or logged anywhere.

Features

✓Generate UUID v4
✓Bulk generation (up to 100)
✓Uppercase / lowercase toggle
✓With or without hyphens
✓UUID validation
✓One-click copy

Frequently Asked Questions

What is a UUID?: A UUID (Universally Unique Identifier) is a 128-bit label standardized by RFC 4122, represented as a 32-character hexadecimal string divided into five groups by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). A UUID generator produces these identifiers for use as unique keys in databases, APIs, and distributed systems.
What is the difference between a UUID and a GUID?: UUID and GUID (Globally Unique Identifier) refer to the same concept — Microsoft coined the term GUID for its implementation of the UUID standard. Both follow the same format and can be generated by the same UUID generator; the terms are interchangeable in practice.
When should I use UUIDs?: Use a UUID generator when you need identifiers that are unique across distributed systems without requiring a central coordinator. Common use cases include database primary keys, session tokens, file names for uploads, message IDs in event queues, and any scenario where sequential integer IDs would expose enumeration risks.
What are the different UUID versions?: UUID v1 is time-based and includes the generating machine's MAC address. UUID v3 and v5 are deterministic, derived from a namespace and name using MD5 or SHA-1 hashing. UUID v4, which this UUID generator produces, is purely random and is by far the most widely used version for general-purpose unique identifiers.
Can two UUIDs ever be the same?: In theory yes, but in practice the probability is astronomically small. A UUID v4 generator draws from a space of 2^122 possible values, making the chance of a collision negligible even when generating billions of IDs. For the vast majority of applications, UUIDs can be treated as globally unique without any additional coordination.

UUID Generator

Validate & Decode UUID

How to Use

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Frequently Asked Questions

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