About this tool
Generate cryptographically random v4 UUIDs.
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal characters. Version 4 UUIDs are randomly generated and the probability of two matching is negligible (1 in 2122). The raw.tools UUID Generator uses the browser's built-in crypto.randomUUID() — cryptographic quality randomness, no server calls.
Example
Click Generate → 550e8400-e29b-41d4-a716-446655440000 (example UUID v4 format)
How to use
- Click Generate to create a single UUID.
- Click Generate ×10 or ×100 for bulk generation.
- Copy individual UUIDs or copy all at once.
- Toggle uppercase / lowercase output.
Features
- UUID v4 using crypto.randomUUID()
- Single or bulk generation (up to 100 at once)
- Uppercase and lowercase options
- Hyphenated and compact formats
- No server calls
Frequently Asked Questions
What is a UUID used for?+
Unique identifiers for database records, session tokens, file names, API keys, and any situation requiring a globally unique ID without a central coordinator.
Are UUIDs truly unique?+
For practical purposes, yes. The probability of two randomly generated UUIDs colliding is 1 in 2122 — negligibly small.
What is UUID v4?+
v4 UUIDs are randomly generated. Other versions: v1 (time-based), v3 (name/MD5), v5 (name/SHA-1). v4 is the most common for general-purpose unique IDs.
What is the difference between hyphenated and compact format?+
The hyphens are standard formatting (8-4-4-4-12 groups). Removing them gives the same value as a 32-character hex string — some systems prefer the compact form.
What is the difference between UUID v1 and v4?+
v1 encodes the current timestamp and MAC address. v4 is fully random — no machine or time information. v4 is preferred when privacy matters.
Are two UUIDs ever the same?+
Extremely unlikely. UUID v4 has 122 random bits (~5.3 × 10³⁶ possible values). The probability of collision across 1 trillion UUIDs is less than 1 in a billion.