UUID Generator
Generate random version 4 UUIDs (also called GUIDs) for database keys, test data and API requests. Create one or up to 1,000 at once, choose the format and copy the list in one click. IDs are made with your browser’s cryptographically secure random generator.
Generate UUIDs
What is a UUID?
A UUID (universally unique identifier) is a 128-bit number written as 32 hexadecimal digits, defined in RFC 9562 (which replaced RFC 4122 in 2024). Microsoft calls the same thing a GUID. Version 4 UUIDs are random, so anyone can create them without a central registry.
UUID v4 format
Layout
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxxThe “4” marks the version, and y is 8, 9, a or b (the variant). The remaining 122 bits are random, giving 2122 ≈ 5.3 × 1036 possible values.
- You would need to generate about 2.7 × 1018 UUIDs for a 50% chance of a single collision.
- At one billion per second, that takes about 86 years.
UUID versions
| Version | Based on | Typical use |
|---|---|---|
| v1 | Timestamp + MAC address | Legacy systems |
| v3 / v5 | MD5 / SHA-1 hash of a name | Same input always gives the same ID |
| v4 | Random | General purpose, most common |
| v7 | Unix time + random | Database keys that sort by creation time |
Frequently asked questions
Are these UUIDs safe to use in production?
Yes. They come from crypto.randomUUID() or crypto.getRandomValues(), the browser’s cryptographically secure generator, and are never sent to or stored on our server.
Is a GUID the same as a UUID?
Yes. GUID is Microsoft’s name; the format is identical, often shown in upper case and wrapped in braces.
Can I use a UUID as a password or secret token?
A v4 UUID has 122 random bits, but it isn’t designed as a secret. Use a dedicated token generator for passwords and API keys.