UUID Generator

Generate unique identifiers for your applications with this free online tool.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

New to this tool? Click here for instructions

Generated UUIDs
Click Generate to create UUID(s).

Quick Answer

A UUID (Universally Unique Identifier) is a 128-bit value written as 36 characters, like 550e8400-e29b-41d4-a716-446655440000, used as a collision-resistant ID with no central authority needed. Version 4 UUIDs are random. Generate one or many above. They make ideal database keys and request IDs, and generation runs entirely in your browser.

How to Use the UUID Generator

The UUID Generator tool is a simple and effective way to generate unique identifiers for your applications. To use the tool, follow these steps:

1. Set the count: Enter how many UUIDs you want to generate (1 to 100).

2. Choose a format: Select lowercase, UPPERCASE, or no dashes.

3. Click Generate: Your UUIDs will appear instantly in the output area.

4. Copy or download: Use Copy All to copy all UUIDs to your clipboard, or Download to save as a text file.

When to Use the UUID Generator

The UUID Generator tool is ideal for various use cases, including:

1. Database primary keys: Avoid auto-increment conflicts in distributed databases.

2. API resource identifiers: Use UUIDs in REST API URLs for non-sequential, non-guessable IDs.

3. Session tokens: Generate unique session identifiers for web applications.

4. File naming: Create unique filenames for uploads to avoid collisions.

5. Message queues: Assign unique identifiers to messages in distributed systems.

6. Correlation IDs: Trace requests across microservices using a shared UUID.

How It Works

The UUID Generator tool uses the browser's Web Crypto API for cryptographically secure random generation. This ensures that the generated UUIDs are unique and cannot be predicted or replicated. The tool supports multiple UUID formats, including lowercase, UPPERCASE, and no dashes. You can easily customize the output to meet your specific needs. The tool is designed to be user-friendly and accessible, with a simple interface that allows you to generate UUIDs quickly and easily.

Frequently Asked Questions

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. UUIDs are formatted as 32 hexadecimal digits displayed in five groups separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). They are also known as GUIDs (Globally Unique Identifiers) in Microsoft ecosystems.
UUID v4 is a randomly generated UUID. All 128 bits (except 6 bits for the version and variant fields) are filled with random data from a cryptographically secure random number generator. This makes collisions extremely unlikely - the probability of generating two identical v4 UUIDs is approximately 1 in 5.3 x 10^36.
While not mathematically guaranteed to be unique, UUID v4 values are generated from 122 random bits, making collisions astronomically unlikely. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision. For all practical purposes, they are unique.
No. UUIDs are generated entirely in your browser using the Web Crypto API (crypto.randomUUID or crypto.getRandomValues). No data is sent to any server. There is no logging and no data collection.
UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) refer to the same concept. UUID is the term used in the RFC 4122 standard and most programming contexts, while GUID is the term commonly used in Microsoft technologies like .NET, SQL Server, and Windows. They are interchangeable.

Quick reference

UUID Generator — quick reference
AspectDetail
PurposeUUID Generator is a free browser tool for fast, repeatable tasks.
Runs inAny modern browser — no install, no signup.
PrivacyData is processed locally in your browser; no upload to any server.
Best forQuick lookups, daily reference, learning, prototyping.