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UUID Generator (v4)

Generate random UUIDs (v4) instantly. Bulk generation supported. Free online UUID tool.

What Is a UUID Generator?

A UUID generator creates Universally Unique Identifiers — 128-bit values used to uniquely identify records, sessions, files, and resources in computer systems. A UUID looks like 550e8400-e29b-41d4-a716-446655440000 and is formatted as five groups of hexadecimal characters separated by hyphens.

This tool generates UUID version 4, which is randomly generated using the browser's Web Crypto API (crypto.randomUUID()). UUID v4 has 122 random bits, giving 5.3 × 10³⁶ possible values. The probability of generating two identical UUIDs is so low that collisions are considered impossible in practice.

UUIDs are used as database primary keys (avoiding sequential ID guessing), session tokens, file names, API request IDs, and anywhere a globally unique identifier is needed without a central authority. Unlike auto-increment integers, UUIDs can be generated on the client side without a database round-trip.

You can generate up to 1,000 UUIDs at once in multiple formats: standard lowercase, UPPERCASE, without hyphens, or wrapped in braces. Bulk results can be copied to clipboard or downloaded as a .txt file.

UUID Versions Explained

Version Method Best for
v1 Timestamp + MAC address Time-ordered records (sortable)
v3 MD5 hash of name Deterministic IDs from names
v4 Random (this tool) General purpose — most common
v5 SHA-1 hash of name Deterministic IDs (more secure than v3)
v7 Timestamp + random Sortable + random (modern databases)

Frequently Asked Questions

What is a UUID?

UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in computer systems. A UUID looks like: 550e8400-e29b-41d4-a716-446655440000. The probability of generating duplicate UUIDs is astronomically low.

What is UUID v4?

UUID version 4 is randomly generated. Unlike v1 (timestamp-based) or v5 (name-based), v4 UUIDs are purely random, making them ideal for most use cases including database primary keys, session IDs, and API tokens.

Are these UUIDs truly unique?

Yes, for all practical purposes. UUID v4 has 122 random bits, giving 2^122 possible values (5.3 × 10^36). The chance of collision is so low that you can safely assume uniqueness.

Can I use these UUIDs in production?

Absolutely. These UUIDs are generated using the Web Crypto API (crypto.randomUUID()), which provides cryptographically strong random values. They're safe for production use.

What's the difference between UUID and GUID?

UUID and GUID (Globally Unique Identifier) are the same thing. Microsoft uses the term GUID, while the rest of the industry uses UUID. They follow the same RFC 4122 standard.

How many UUIDs can I generate at once?

You can generate up to 1000 UUIDs in a single batch. For larger quantities, run the generator multiple times.

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