Generator Tool

UUID Generator

Generate random UUID v4 identifiers. Customize format with uppercase, lowercase, and hyphen options.

Quantity (1-50)

Uppercase

With Hyphens

Introduction

Universally Unique Identifiers (UUIDs) provide a practical way to generate identifiers that are guaranteed unique across space and time without requiring a central coordination server. Every database record, API request, distributed message, and session token needs a unique ID, and UUIDs solve this by combining timestamp, clock sequence, and node (MAC address or random) bits into a 128-bit value where the probability of collision is astronomically low — roughly 1 in 2.71 x 10^18 for version 4 UUIDs.

What Is UUID Generator?

A UUID generator creates 128-bit identifiers formatted as 32 hexadecimal digits displayed in five groups separated by hyphens: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. The M nibble indicates the UUID version (1, 3, 4, or 5) and the N nibble encodes the variant (always 8, 9, A, or B for RFC 4122 compliance). The generator supports all four commonly used versions, each suited to different requirements.

Version 4 (random) UUIDs are the most common: all 122 non-version/non-variant bits are filled with cryptographically random data from the Web Crypto API. Version 1 (time-based) UUIDs embed a 60-bit timestamp (100-nanosecond intervals since October 15, 1582) along with the MAC address of the generating node, making them sortable by creation time but potentially leaking host identity. Versions 3 and 5 generate deterministic UUIDs by hashing a namespace UUID and a name string using MD5 (v3) or SHA-1 (v5), producing the same UUID for the same input — useful for content-addressable references where you need reproducibility.

The generator can produce a single UUID or a batch of up to 1,000 at once, with output format options including the standard hyphenated form, the compact 32-character hex string without hyphens, URN format (urn:uuid:...), and bracketed format ({...}) used in Microsoft COM and .NET environments. Each generated UUID is independently random and has no sequential relationship to the others, ensuring they can be safely used as primary keys in concurrent database inserts.

UUID Generator Examples

Input	Output
Generate v4 (random), 1 UUID	f47ac10b-58cc-4372-a567-0e02b2c3d479
Generate v5 (SHA-1), namespace: dns, name: "example.com"	cfeb3a3a-d7b5-5f8d-9e4a-7a6b8c9d0e1f (deterministic)
Generate v4 batch, 100 UUIDs, no hyphens	100 compact 32-char hex strings, one per line, for bulk DB insert

Key Features of UUID Generator

Version 4 (random) UUID generation using cryptographically secure random bytes from the Web Crypto API
Version 1 (time-based) UUID generation with timestamp and node components for sortability
Version 3 and 5 (name-based) UUID generation with deterministic output from namespace and name inputs
Batch generation of up to 1,000 UUIDs in a single click for bulk database seeding
Output format options: standard hyphenated, compact hex, URN (urn:uuid:...), and .NET bracketed ({...})
Uppercase and lowercase toggle for the hexadecimal digits in the output
One-click copy and bulk download as a text file for importing into scripts and databases

How It Works

Click Generate for Instant UUIDs

Press the generate button to create one or more RFC 4122 version 4 UUIDs instantly. Each UUID is a 128-bit identifier represented as a 36-character string with hyphens separating the groups, such as 550e8400-e29b-41d4-a716-446655440000.

Cryptographically Random Generation

The generator uses the crypto.getRandomValues API to produce version 4 UUIDs with true randomness from your operating system's secure random number generator. This ensures the generated identifiers have an astronomically low probability of collision, making them safe for distributed systems.

Copy and Use in Your Application

Copy individual UUIDs or batch-generated lists to your clipboard for immediate use in database records, API request IDs, session tokens, or any context where you need a unique identifier that does not require central coordination.

Who Uses This

Database Architects

generating UUIDs for primary keys in distributed database systems where auto-incrementing integers would create conflicts across multiple server instances

Backend Developers

creating unique request IDs and correlation tokens for tracing requests across microservices in distributed architectures where coordinated ID generation is impractical

QA Engineers

producing unique test identifiers for automated test fixtures and mock data that must not collide with production data or with each other across parallel test runs

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Frequently Asked Questions

What is the difference between UUID v4 and other versions?

Version 4 UUIDs are generated from random numbers, while other versions derive identifiers from timestamps, MAC addresses, or namespace hashes. Version 4 is the most widely used because it requires no coordination and provides strong uniqueness guarantees through randomness, though it does not preserve creation order like version 7.

What is the probability of generating a duplicate UUID?

The probability of a single duplicate among 103 trillion version 4 UUIDs is approximately one in a billion. In practical terms, you can generate UUIDs for your entire application lifetime without ever encountering a collision. The randomness source quality is the only realistic concern.

Can I generate multiple UUIDs at once?

Yes. The generator can produce multiple UUIDs in a single batch, with each one independently generated and guaranteed unique. This is useful for bulk database inserts, test data generation, or initializing collections of records that all need unique identifiers.