UUID Generator
Description
Generate UUIDs of all versions: NIL, v1 (time), v3/v5 (name-based), v4 (random). Bulk generation up to 50 with custom namespaces.
About UUID Generator
The UUID Generator creates universally unique identifiers of every version — NIL, v1 (time-based), v3 (name-based MD5), v4 (random), and v5 (name-based SHA-1) — directly in your browser. A UUID is a 128-bit value written as 36 characters (e.g. 550e8400-e29b-41d4-a716-446655440000) that is unique enough to assign without a central authority. Generate one or many at once for database keys, request IDs, or test data.
How to use
- Choose the UUID version you need (v4 random is the most common).
- For v3/v5, provide a namespace and a name — the same inputs always produce the same UUID.
- Set how many to generate (bulk up to 50) and click generate.
- Copy a single value or the whole list.
Examples
| Example | Input | Output |
|---|---|---|
| v4 (random) | — | 9b2e4f6a-1c3d-4e5f-8a7b-2c1d0e9f8a7b |
| NIL | — | 00000000-0000-0000-0000-000000000000 |
Frequently asked questions
Which UUID version should I use?
v4 (random) is the default for most applications — keys, request IDs, tokens. Use v5 when you need a deterministic UUID derived from a name. v1 embeds a timestamp and MAC address and is rarely needed today.
Are random (v4) UUIDs really unique?
Practically, yes. A v4 UUID has 122 random bits, so the chance of a collision is astronomically small even across billions of values. They are generated here with the browser's cryptographic random source.
What's the difference between a UUID and a GUID?
None in practice. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit standard; the formats are interchangeable.
Can a UUID be used as a database primary key?
Yes, though random v4 UUIDs can fragment B-tree indexes. If insert ordering matters, consider a time-sortable identifier like ULID instead.