UUID Generator
Generate one or hundreds of random v4 UUIDs.
0 random version-4 UUIDs
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value used to identify information without a central registry — the same ID essentially never gets generated twice, even across millions of machines generating them independently. This tool generates version 4 UUIDs, the most common kind, where 122 of the 128 bits are cryptographically random.
How to generate UUIDs
- 1Set how many you need (1 to 500).
- 2Click Regenerate to create a fresh batch.
- 3Toggle Uppercase or No hyphens if your system expects a different format.
- 4Copy a single UUID, Copy all, or Download the full list as a .txt file.
Where UUIDs are used
Database primary keys, distributed systems that need IDs without coordinating with a central server, session tokens, file names for uploads, and request-tracing IDs are all common uses. Because v4 UUIDs are random rather than sequential, they also avoid leaking information like creation order or row counts.
Frequently asked questions
›How random are these UUIDs?
They're generated with crypto.randomUUID(), which uses the browser's cryptographically secure random number generator — the same quality of randomness used for encryption keys, not Math.random().
›What's the chance of a collision?
For version-4 UUIDs, you'd need to generate around 1 billion per second for about 85 years before the probability of a single collision reaches 50% (roughly 2^122 possible values). In practice, treat them as unique.
›Why remove the hyphens?
Some systems, database columns or ID formats expect a plain 32-character hex string instead of the standard 8-4-4-4-12 hyphenated format. The No hyphens option strips them for you.
›Can I generate UUIDs in other versions, like v1 or v7?
This tool only generates v4 (random) UUIDs, which is what crypto.randomUUID() produces and what almost every modern use case calls for. v1 (timestamp-based) and v7 (sortable) need different generation logic and aren't currently supported here.
›Is there a limit to how many I can generate at once?
Up to 500 per batch, to keep the page responsive. Click Regenerate again for another batch, or download the list and repeat as many times as you need.