Bulk Cryptographic UUID v4 Generator

UUID v4 Mathematics and Collision Probability

A Version 4 UUID is a 128-bit identifier composed of 32 hexadecimal digits displayed in five hyphen-separated groups (8-4-4-4-12). Out of the 128 bits, 6 bits are fixed to denote the version (4) and variant (RFC 4122 / RFC 9562), leaving 122 bits of true cryptographic entropy. This provides 2¹²² possible combinations — approximately 5.3 × 10³⁶ distinct identifiers.

The probability of generating a duplicate UUID v4 is so vanishingly small as to be practically impossible. Generating one billion UUIDs every second for 100 consecutive years yields a collision probability of less than 0.0000000000001 (one in ten trillion). This makes UUID v4 the gold standard for distributed database primary keys where centralized coordination is unfeasible.

Cryptographic Entropy vs. Insecure Math.random()

Many basic online UUID generators rely on JavaScript's pseudo-random number generator, Math.random(), which is neither cryptographically secure nor guaranteed to avoid periodicity cycles. In contrast, our generator exclusively invokes window.crypto.randomUUID(), tapping directly into your operating system's kernel-level entropy pool (e.g., /dev/urandom on Unix or CryptGenRandom on Windows).

This ensures that every generated key is safe for production use in session tokens, API request tracing IDs, and sensitive database entity IDs.

Step by step: how to use UUID Generator

1. 1

   Select the number of UUIDs to generate (from 1 to 1,000 keys).

2. 2

   Choose your casing: lowercase (standard) or uppercase.

3. 3

   Toggle hyphens on or off depending on your database schema requirements.

4. 4

   Select output formatting: Plain List, Comma-Separated, or JSON Array.

5. 5

   Click 'Copy All' to copy the batch to your clipboard, or click 'Download .txt' to export a file.

Frequently asked questions