About UUID Generator
A UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a 128-bit number used to uniquely identify information in computer systems. The standard format is 32 hexadecimal digits in five groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
UUID v4 (recommended) is randomly generated using cryptographically secure random numbers — the probability of collision is astronomically small. UUID v1 is based on the current timestamp and MAC address — useful when you need UUIDs to sort chronologically.
Uses the browser's native crypto.randomUUID() API — no libraries needed, cryptographically secure.
Updated: May 2025 · Works on Chrome, Firefox, Safari, Edge · Mobile friendly
Frequently Asked Questions
Are UUIDs truly unique?+
UUID v4 has 2^122 possible values — about 5.3×10^36. The probability of generating a duplicate UUID is so small it is practically impossible. You could generate a billion UUIDs per second for 85 years before a collision becomes likely.
When should I use UUID v1 vs v4?+
Use v4 for general purpose unique IDs (database primary keys, session tokens, file names). Use v1 when you need UUIDs to be sortable by creation time — useful for time-series data or distributed systems that need ordering.
What is the difference between UUID and GUID?+
They are the same thing. UUID is the open standard term (RFC 4122). GUID is Microsoft's implementation name. Both have the same format and properties.
Are these UUIDs safe to use as database primary keys?+
Yes — UUID v4 is widely used as database primary keys, especially in distributed systems where auto-increment integers could conflict. Note that random UUIDs don't sort well in B-tree indexes; consider UUID v7 (ordered) for large databases.