UUID Generator

Generate universally unique identifiers in various formats.

UUID Options

Generate universally unique identifiers in various formats.

Quantity

Format

Generated UUIDs

Click Copy All to copy all UUIDs to your clipboard.

Click Generate to create UUIDs.

Stats

Quantity generated

Standard

Format used

Total characters

About UUIDs

UUID v4 provides 2^122 possible combinations. The chance of collision is astronomically low.
Use UUIDs for database primary keys, session IDs, or any case where you need guaranteed unique identifiers.

What Is a UUID Generator

A UUID (Universally Unique Identifier) generator creates 128-bit identifiers that are guaranteed to be unique across all systems, all time, without requiring a central authority to issue them. This makes UUIDs ideal for distributed systems, databases, APIs, and any application where you need to create identifiers independently without risk of collision.

This generator produces UUID v4 identifiers, which use cryptographically secure random numbers. With 2^122 possible combinations (over 5 undecillion values), the probability of generating two identical UUIDs is so low it is effectively zero — even if you generated a billion UUIDs per second for a hundred years.

When to Use UUIDs

UUIDs are the standard choice when you need unique identifiers that can be generated independently across multiple servers, clients, or services. Common use cases include database primary keys (especially in distributed databases), API resource identifiers, session tokens, file naming, message queue deduplication, and correlation IDs for distributed tracing.

UUIDs are particularly valuable in microservice architectures where multiple services need to create records simultaneously without coordinating with a central ID authority. They also work well for client-side ID generation — mobile apps and browsers can create UUIDs locally before syncing data to the server, eliminating round-trip delays.

How to Use This UUID Generator

Set the quantity of UUIDs you need (up to 100 at a time) and choose your preferred format. Standard format includes dashes in the canonical 8-4-4-4-12 pattern. No Dashes removes the hyphens for compact storage. Uppercase converts to capital letters for systems that expect it. With Braces wraps the UUID in curly braces as used in Microsoft systems.

Click Generate to create a fresh batch. Copy individual UUIDs by clicking the copy button next to each one, or use Copy All to grab the entire batch separated by newlines. The generator uses your browser's cryptographic random number generator (crypto.randomUUID or crypto.getRandomValues) for secure, high-quality randomness.

UUID Versions Explained

UUID v1 uses the current timestamp and the machine's MAC address, making each UUID traceable to a specific device and moment. UUID v4 (what this tool generates) uses purely random data, offering better privacy since no identifying information is embedded. UUID v5 generates deterministic IDs by hashing a namespace and name, useful when you need the same input to always produce the same UUID.

For most applications, UUID v4 is the best choice. It provides strong uniqueness guarantees without leaking timing or hardware information. UUID v7 is a newer standard that combines timestamp ordering with randomness, making it ideal for database primary keys where sort order matters — but v4 remains the most widely supported and understood version.

Frequently Asked Questions

What is the difference between UUID v4 and v1?

UUID v4 is generated from random data, while UUID v1 combines a timestamp with the machine's MAC address. V4 is preferred for most applications because it does not leak hardware or timing information. V1 is useful when you need time-ordered identifiers, but UUID v7 is now the better choice for time-ordered use cases.

Can two UUIDs ever be the same?

Theoretically yes, but practically no. UUID v4 has 2^122 possible values. The probability of a collision is roughly 1 in 2.7 quintillion after generating 103 trillion UUIDs. You would need to generate 1 billion UUIDs per second for about 85 years before reaching a 50% chance of a single duplicate.

Are UUIDs secure for use as tokens?

UUID v4 generated with cryptographic random sources (as this tool does) are unpredictable and safe for non-critical token use. However, for security-sensitive tokens like API keys or password reset links, purpose-built token generators with higher entropy and built-in expiration are recommended over plain UUIDs.

What is the format of a UUID?

A standard UUID is a 128-bit value displayed as 32 hexadecimal characters in five groups separated by dashes: 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). The total string length is 36 characters including dashes, or 32 characters without. The version number appears as the first digit of the third group.

Should I use UUIDs or auto-increment IDs?

Auto-increment IDs are simpler and more storage-efficient but require a central database to assign them. UUIDs can be generated anywhere without coordination, making them essential for distributed systems. The tradeoff is size (16 bytes vs 4-8 bytes) and index performance. For single-database applications, auto-increment works fine. For distributed systems, microservices, or client-side generation, use UUIDs.

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UUID Generator

Generate universally unique identifiers in various formats.

UUID Options

Generate universally unique identifiers in various formats.

Quantity

Format

Generated UUIDs

Click Copy All to copy all UUIDs to your clipboard.

Click Generate to create UUIDs.

Stats

Quantity generated

Standard

Format used

Total characters

About UUIDs

UUID v4 provides 2^122 possible combinations. The chance of collision is astronomically low.
Use UUIDs for database primary keys, session IDs, or any case where you need guaranteed unique identifiers.