Online UUID & GUID Generator (v4 & v7)
Generate RFC 4122 Version 4 random UUIDs and modern RFC 9562 Version 7 timestamp-ordered UUIDs instantly. All values are generated locally on your device via the Web Crypto API. Tokens are never transmitted to remote servers.
#How to Use This Tool
#Mathematical Formula & Standards
#Edge Cases & Technical Considerations
Collision Probability in UUID v4
With 122 bits of entropy ($2^{122} \approx 5.3 \times 10^{36}$ unique IDs), the probability of generating a duplicate UUID v4 is negligible (generating 1 billion UUIDs per second for 85 years yields a 50% probability of a single collision).
Database B-Tree Performance: UUID v7 vs v4
Standard UUID v4 causes random page splits and write amplification in database primary keys (PostgreSQL, MySQL, SQLite). UUID v7 orders keys monotonically by insertion time, offering the insertion speed of auto-incrementing integers with the uniqueness of UUIDs.
Client-Side CSPRNG Security
Generation relies strictly on window.crypto.getRandomValues(). Math.random() is never utilized, eliminating pseudorandom seed prediction vulnerabilities.
#Frequently Asked Questions
Q:What is the difference between UUID v4 and UUID v7?
UUID v4 is completely random. UUID v7 combines a 48-bit Unix timestamp with random bits, making it naturally chronological and ideal for database primary keys.
Q:Are UUIDs generated on this website secure and private?
Yes. Everything runs 100% on your device using the browser Web Crypto API. The generated UUIDs are never sent to our servers or saved anywhere.
Q:Are UUID and GUID the same thing?
Yes. GUID (Globally Unique Identifier) is Microsoft’s terminology for the standardized UUID (Universally Unique Identifier).