UUID Generator – Free Online UUID v4 & GUID Creator Tool

Generate UUID v4 (Universally Unique Identifier) strings instantly in your browser using the cryptographically secure crypto.randomUUID() API. Generate 1 to 100 UUIDs at once and choose from 5 output formats: Standard (lowercase with hyphens), Uppercase, No Hyphens (32-char hex), Braces (Microsoft/COM style), or URN (RFC 4122). Copy individual UUIDs on hover or copy all at once with a single click. The built-in Validate tab checks any UUID for correct format, version (v1–v5), and RFC 4122 variant. Perfect for developers creating database primary keys, session tokens, file names, API resources, and distributed system identifiers.

Output Format

max 100
5 UUIDs Generated
148756186-6069-4413-ac2c-96b61943ee5b
2d312ff14-a20b-420b-9eb8-0e6950f1f96b
3dfd8880d-1412-46d3-986e-53b04d995315
4044a5b7c-a360-44c1-90af-f4a13a68a959
56ee9ceaf-fb9e-4a16-a810-575a026be41b
🔒 100% in-browser — no data is ever sent to any server
UUID v4 (Universally Unique Identifier, version 4) uses crypto.randomUUID() — a cryptographically secure random source. With 2¹²² possible values, the probability of collision is astronomically low. UUIDs are standardized by RFC 4122.

How to Use the UUID Generator

Generate UUIDs:

  1. Choose your preferred output format: Standard (hifenado), Uppercase, No Hyphens, Braces, or URN.
  2. Set the quantity — type a number between 1 and 100, or click a quick preset pill (1, 5, 10, 25, 50, 100).
  3. Click Generate to produce all UUIDs at once.
  4. Hover any row and click its Copy button to copy that specific UUID, or click Copy all at the top of the results list to copy every UUID (one per line).
  5. Click Regenerate to instantly produce a fresh set without changing settings.

Validate a UUID:

  1. Click the Validate UUID tab.
  2. Paste any UUID string — standard, uppercase, with braces {...}, or URN format.
  3. The result shows whether it is valid and, if so, the version (v1, v3, v4, v5…) and variant (RFC 4122 standard, Microsoft GUID, NCS legacy, or Reserved).

Output formats explained:

  • Standard — lowercase with hyphens: 550e8400-e29b-41d4-a716-446655440000 (most common)
  • Uppercase — same but uppercase: 550E8400-E29B-41D4-A716-446655440000
  • No Hyphens — compact 32-char hex: 550e8400e29b41d4a716446655440000 (used in some database columns)
  • Braces — Microsoft/COM style: {550e8400-e29b-41d4-a716-446655440000}
  • URN — RFC 4122 URN namespace: urn:uuid:550e8400-...

What is a UUID?

  • A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems, standardized by RFC 4122.
  • Version 4 (v4) is randomly generated using a cryptographically secure source (crypto.randomUUID()). With 2¹²² possible values (~5.3 × 10³⁶), collisions are practically impossible.
  • UUIDs are used everywhere: database primary keys, session tokens, file names, API resources, distributed systems, and anywhere a globally unique ID is needed without a central coordinator.
  • The "4" in position 13 identifies the version; the character in position 17 (8–b) identifies the RFC 4122 variant.