UUID Generator
Generate RFC 4122 UUIDs in bulk. Version 4 (random) and version 7 (time-ordered) using cryptographically secure randomness.
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About this tool
This free online tool runs entirely in your browser. Your data never leaves your device — there is no server processing, no tracking, and no signup required. Use it as often as you need, on any device.
· Maintained by the Forge Engineering Team
How This Calculator Works
This tool generates UUIDs (Universally Unique Identifiers) as defined in RFC 9562 (which replaced RFC 4122). It supports UUIDv4 (random, 122 bits of randomness from crypto.getRandomValues()) and UUIDv7 (time-ordered, combining a Unix timestamp with random bits for better database index locality). All UUIDs are generated entirely in your browser using cryptographically secure randomness.
Frequently Asked Questions
What is the difference between UUIDv4 and UUIDv7?
UUIDv4 is fully random — great for avoiding collisions but bad for database indexes (random insertion order causes index fragmentation). UUIDv7 (RFC 9562, 2024) embeds a millisecond timestamp, making UUIDs time-sortable and database-friendly. UUIDv7 is recommended for new database-primary-key use cases.
Can UUIDs collide?
The probability is astronomically low. A UUIDv4 has 122 random bits. The chance of a collision among 103 trillion UUIDs is still about 50%. For practical purposes, collisions are effectively impossible. You can safely use them as database primary keys.
Is UUID the same as GUID?
Yes, functionally identical. UUID is the IETF/RFC term. GUID is the Microsoft term. Both are 128-bit identifiers formatted as 36 characters (8-4-4-4-12) with hyphens, e.g., 550e8400-e29b-41d4-a716-446655440000. The byte representation may differ in endianness on some systems.
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