UUID generator
Generate random v4 UUIDs in bulk.
- Instant
- Free
- Private (processed locally)
- No sign-up
Unique identifiers, on demand
UUIDs are everywhere in development: database keys, object identifiers, tokens. This tool generates as many as you need, instantly, with a cryptographic randomness source.
How to use it
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Choose the quantity
From 1 to 100 UUIDs at once.
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Set the format
Uppercase and hyphens as needed.
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Copy
One UUID at a time, or the whole list at once.
Anatomy of a v4 UUID
| Property | Detail |
|---|---|
| Length | 36 characters (32 hex + 4 hyphens) |
| Format | 8-4-4-4-12 (e.g. xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx) |
| Version | The 13th character is always “4” |
| Randomness | 122 bits from Web Crypto |
Use cases
- Databases: primary keys with no collision risk.
- APIs and files: unique names, request tokens.
- Testing: generate fake data sets.
Frequently asked questions
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit identifier written as 36 characters (32 hexadecimal digits and 4 hyphens). It uniquely identifies an item without central coordination.
What is version 4?
A v4 UUID is generated (pseudo-)randomly. It is the most common version because it needs neither a hardware address nor a clock: a good source of randomness is enough.
Can two UUIDs be identical?
In theory yes, in practice no. With 122 random bits, the collision probability is so tiny it is negligible, even when generating billions of identifiers.
Is the randomness reliable?
Yes. The tool uses crypto.randomUUID (or crypto.getRandomValues as a fallback), the browser’s cryptographic generator, far safer than Math.random.
Are the UUIDs sent online?
No. They are generated locally and never leave your device.