How is a UUID v4 generated on this site?

All UUID generation runs completely client-side in your browser. We prioritize the standard modern browser method crypto.randomUUID(). If that API is unavailable or disabled, we employ a secure fallback using cryptographically strong bytes retrieved from crypto.getRandomValues().

Is there a limit on bulk generation?

Yes, we enforce a strict single-click limit of 500 UUIDs. This restriction is designed to ensure extremely fast render performance and prevent page lag on mobile viewports.

What does a version-4 UUID consist of?

A version 4 UUID is a 128-bit random number represented by 32 hexadecimal characters separated by four hyphens. It strictly defines the version byte (always '4' at character 15) and the variant indicator (8, 9, a, or b at character 20) under RFC 4122 specifications.

UUID v4 Generator

100% Client-Side

Generate cryptographically secure, random version 4 UUIDs (GUIDs) instantly in bulk. No tracking, completely offline.

Bulk Options

Number of UUIDs to Generate

Select a quantity from 1 to 500 tokens in a single batch.

Cryptographic Strength

Method: CSPRNG (Web Crypto API)

Generated UUID List

Frequently Asked Questions

What is a UUID version 4?

A Universally Unique Identifier (UUID) version 4 is a standard random number identifier generated based on cryptographically secure random values. Its mathematical length makes collisions practically impossible.

Are UUIDs generated on this tool secure for database keys?

Yes, absolutely. The tool relies exclusively on the browser's native Web Crypto CSPRNG APIs (either crypto.randomUUID() or strong fallbacks with crypto.getRandomValues()), ensuring high randomness and compliance for production systems.

Is there a difference between a GUID and a UUID?

A Globally Unique Identifier (GUID) is Microsoft's implementation of the UUID standard. Practically, GUID and UUID version 4 are identical in length, format, and random bit structure.

Mathematical Odds of UUID v4 Collisions

A version 4 UUID contains 122 random bits of entropy (out of 128 bits total). The number of possible distinct keys is 2¹²², which is roughly 5.3 × 10³⁶ keys.

To put this in perspective: to achieve a 50% probability of finding a single duplicate, you would need to generate 2.71 quintillion UUIDs every second for the next 100 years. It is highly secure for database indexes and transaction identifiers.

Structure of a UUID version 4

An RFC 4122 UUID v4 follows the xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx template format, consisting of five groups of hex numbers:

The first 8 characters represent random hex strings.
The second group consists of 4 random characters.
The third group starts with a constant 4 (which designates version 4).
The fourth group begins with 8, 9, a, or b (which designates the standard RFC 4122 variant).
The final block consists of 12 random hex characters.