UUID Generator
Generate random UUID v4 values — single or bulk up to 100. Free — runs entirely in your browser.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used in software to uniquely identify information. UUID v4 is the most commonly used version, generated using random or pseudo-random numbers. The probability of generating two identical UUIDs is astronomically small — roughly 1 in 5.3 × 10³⁶.
UUIDs are used as primary keys in databases, session tokens, API keys, file names, transaction IDs, and anywhere a unique identifier is needed without a central authority to assign them. They follow the format: 8-4-4-4-12 hexadecimal digits separated by hyphens.
Frequently Asked Questions
What is UUID v4?▼
UUID v4 is generated using random or pseudo-random numbers. It has the format xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where 4 indicates version 4 and y is one of 8, 9, a, or b.
Are UUIDs truly unique?▼
For all practical purposes, yes. The chance of generating a duplicate UUID v4 is 1 in 5.3 × 10³⁶, which is negligible even at massive scale.
Can I use UUIDs as database primary keys?▼
Yes, UUIDs are excellent primary keys for distributed systems where you cannot rely on auto-incrementing integers. The tradeoff is they are larger (16 bytes vs 4 or 8 bytes for integers).
Is this generator free?▼
Yes, 100% free. Generated in your browser with no data sent anywhere.