UUID Generator
Generate UUID v4 values. Supports bulk generation.
About the UUID Generator
The UUID Generator instantly creates cryptographically random Version 4 UUIDs (Universally Unique Identifiers). Generate a single UUID or up to 1,000 in bulk and copy them all at once. No installation, no sign-up, and no data is sent anywhere.
A UUID is a 128-bit identifier formatted as 32 hexadecimal characters grouped by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUID v4 uses a cryptographically secure random number generator, making collisions astronomically unlikely — the probability of generating two identical v4 UUIDs is lower than one in a quintillion. UUIDs are the standard choice for database primary keys, session tokens, file names, and any scenario where unique IDs must be generated across distributed systems without coordination.
All UUIDs are generated using the browser's native crypto.randomUUID() function, which uses a cryptographically secure pseudorandom number generator (CSPRNG). Nothing leaves your browser.
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122, formatted as 32 hexadecimal characters in 5 groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
What is UUID v4?
UUID v4 is randomly generated using a cryptographically secure random number generator, with two specific bits set to mark it as version 4. It has no meaning encoded in the bits — it is purely random, unlike v1 (timestamp-based) or v5 (name-based).
Are UUIDs truly unique?
In practice, yes. The probability of generating two identical v4 UUIDs is approximately 1 in 2¹²² (about 5.3 × 10³⁶). Generating a billion UUIDs per second for the next 100 years would still yield a collision probability less than one in a billion.
Can I use UUIDs as database primary keys?
Yes. UUIDs are widely used as primary keys in distributed databases where auto-increment integers would require coordination across shards. The tradeoff is larger storage size (16 bytes vs. 4–8 bytes for integers) and potentially worse index locality on sequential scans.
What is the difference between UUID and GUID?
GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. A GUID is a UUID. The terms are interchangeable — GUIDs follow the same RFC 4122 format and are commonly generated as v4.