UUID Generator
Last updated: 2026-06-25
The UUID generator is a free tool that creates as many RFC 4122 version 4 (v4) UUIDs (GUIDs) as you want, all at once.
It uses secure randomness (crypto.randomUUID / getRandomValues), and every UUID is generated in your browser.
Generate UUIDs
Generated UUIDs
How to use
- Enter a count — enter how many UUIDs (1–1000) to generate at once.
- Run generation — click Generate UUIDs to show that many v4 UUIDs, one per line.
- Copy — click the copy button to copy all generated UUIDs to the clipboard at once.
What is a UUID
A UUID (Universally Unique Identifier) is a 128-bit value for creating unique identifiers without coordination between systems. It is written as a 36-character string in 8-4-4-4-12 form (e.g. 550e8400-e29b-41d4-a716-446655440000) and is widely used for database primary keys, identifiers in distributed systems, and file or session IDs.
| Version | How it is generated | Use |
|---|---|---|
| v1 | Time + MAC address | When time-ordered IDs are needed |
| v4 | Random | Most common, general identifiers |
| v5 | Namespace + name hash | Deterministic identifiers |
This tool generates the most common v4 (random) UUIDs. The 13th character is always 4 (version) and the 17th is one of 8, 9, a, b (variant). If you need a hash, use the hash generator; for arbitrary text encoding, use the Base64 encoder.
Frequently asked questions (FAQ)
How is a v4 UUID generated?
A v4 UUID is generated from 122 bits of randomness. This tool prefers the browser's crypto.randomUUID and, where unsupported, uses crypto.getRandomValues for secure randomness to build a v4 UUID that conforms to RFC 4122.
Are UUID and GUID different?
They are effectively the same. GUID (Globally Unique Identifier) is the name used in Microsoft ecosystems, while UUID (Universally Unique Identifier) is the standard term. The format (8-4-4-4-12, 36 characters total) is identical.
Is there any chance UUIDs collide?
It is theoretically possible but practically negligible. The number of possible v4 UUIDs is about 5.3×10^36, so the probability of a collision in normal usage is essentially zero.
How many can I generate at once?
This tool can generate from 1 up to 1000 at once. All UUIDs are generated in your browser and are never sent to a server.
Related tools & guides
Last updated: 2026-06-25