UUID Generator
This free UUID generator creates a random UUID (version 4, also called a GUID) with one click, or a whole batch at once. Everything runs locally in your browser using a cryptographically secure random number generator — nothing is sent anywhere.
What is a UUID (and a GUID)?
A UUID is a 128-bit identifier written as 32 hex digits split into five
groups, such as 3fa85f64-5717-4562-b3fc-2c963f66afa6. It exists
so that any system — a database, an API, a distributed set of servers — can
mint a unique ID for a new record without checking in with a central
counter first. GUID is simply Microsoft's name for the same format; the two
terms are interchangeable in practice. The format is standardised in
RFC 9562, which in 2024
replaced the original RFC 4122.
Version 4 UUIDs: random and (practically) collision-free
This generator produces version 4 UUIDs — the version built entirely from random bits rather than a timestamp or network address, which is what the vast majority of modern applications use. With 122 random bits, the chance of two independently generated UUIDs ever colliding is small enough to ignore for essentially any real-world workload.
Formatting options: hyphens, case, and braces
The default output matches the standard format most systems expect. Toggle
Remove hyphens for a compact 32-character string, tick
Uppercase if your target system expects capital hex digits,
or add Wrap in braces for the {...}
format some Windows APIs and COM interfaces use for GUIDs.
Private by design
Generation happens entirely in your browser via the Web Crypto API — no UUID you create here is ever sent over the network, logged, or stored. If you need to inspect an existing identifier-bearing token instead, try our JWT decoder or Base64 encoder/decoder.
Frequently asked questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value written as 32 hexadecimal digits in five groups — 8-4-4-4-12 — like 3fa85f64-5717-4562-b3fc-2c963f66afa6. It is used to identify a database row, an API resource, a session, or any object without needing a central authority to hand out the next number, because the odds of two random UUIDs colliding are astronomically small.
What's the difference between a UUID and a GUID?
They are effectively the same thing. GUID (Globally Unique Identifier) is the name Microsoft uses in Windows and .NET; UUID is the name used everywhere else, including the formal IETF standard (RFC 9562). The format and generation methods are identical, so a UUID generated here works anywhere a GUID is expected.
What version of UUID does this generate?
Version 4 — fully random. This is by far the most commonly used version today: every one of the 122 free bits is generated with a cryptographically secure random number generator, with no dependency on your system clock or network hardware address (unlike version 1, which encodes both and can leak information about when and where it was created).
Are the generated UUIDs guaranteed to be unique?
Not mathematically guaranteed, but as close as makes no practical difference. A version 4 UUID has 122 random bits, giving roughly 5.3 undecillion (5.3 × 10^36) possible values. You would need to generate around a billion UUIDs per second for about 85 years before the chance of a single collision reached even one in a billion — collisions are not a realistic concern for normal use.
Can I generate many UUIDs at once?
Yes. Use the bulk section below the main generator to create up to 1000 UUIDs at once (5, 10, 20, 50, 100, 250, 500, or 1000), each with its own copy button, plus a "Copy all" button and a Download button (uuids.txt, one per line) to grab the whole list — handy for seeding test data or filling out a spreadsheet.
Is it safe to generate UUIDs in my browser, and is anything sent to a server?
Yes — this tool uses the Web Crypto API's cryptographically secure random source (crypto.randomUUID(), with a crypto.getRandomValues() fallback on pages that are not served over HTTPS), so the output is suitable for real IDs rather than just placeholders. Everything runs locally; no UUID you generate is transmitted, logged, or stored anywhere. Working with encoded tokens instead? Try our Base64 encoder or JWT decoder.