🆔 UUID Generator
Generate random (v4), time-ordered (v7), classic (v1) or deterministic (v5) UUIDs in bulk — with formatting options and a breakdown of how each one is built. Free, instant & 100% private.
Enter a name to generate a v5 UUID.
🔬 Anatomy of this UUID
A UUID is 128 bits shown as 32 hex characters in 8-4-4-4-12 groups. One digit marks the version (how it was made) and the next group starts with the variant. v4 packs 122 random bits — the rest are fixed version/variant markers.
More Than a Random String
Every UUID version, bulk output, secure randomness and a look under the hood — in one fast, private page.
Every Version
Random v4, time-ordered v7, classic v1, deterministic v5 and the NIL UUID — all in one place.
Bulk Generation
Need a thousand at once? Set the count and generate them instantly, then copy all or download a .txt.
Crypto-Secure
Random bits come from the Web Crypto API — the same secure source used for keys, not Math.random().
Anatomy View
See exactly how a UUID is built, with the version and variant digits highlighted in the live sample.
Formatting Options
Uppercase, strip hyphens, or wrap in braces to match whatever your code or database expects.
Private & Free
100% in your browser — nothing is sent or stored. No login, no limits, dark mode, responsive to 280px.
How to Generate a UUID
Four steps — results appear the instant you choose a version.
Choose a version
v4 for general use, v7 for database keys, v5 for deterministic IDs, or v1 / NIL.
Set the quantity
Generate one or up to a thousand at a time — handy for seeding data or testing.
Tweak the format
Toggle uppercase, hyphens or braces so the output drops straight into your code.
Copy or download
Tap a single UUID to copy it, or grab the whole batch with Copy all / Download.
Frequently Asked Questions
What a UUID is, choosing a version, v4 vs v7, v5 explained, randomness, collision odds and privacy.
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit value written as 32 hexadecimal characters in a 8-4-4-4-12 pattern, like 550e8400-e29b-41d4-a716-446655440000. It's designed so that anyone, anywhere, can generate one without a central authority and be confident it won't clash with anyone else's.
How do I generate a UUID here?
Pick a version (v4 is the usual choice), set how many you want, and they appear instantly below. Tap any UUID to copy it, or use 'Copy all' / 'Download .txt' for the whole batch. Hit 'Generate new' for a fresh set. The formatting checkboxes let you switch to uppercase, remove hyphens, or wrap each in braces.
Which UUID version should I use?
v4 (random) is the safe default for almost everything — IDs, keys, tokens. v7 is newer and time-ordered, which makes it far better as a database primary key because new rows sort in insertion order and index more efficiently. v1 is the classic timestamp-based version. v5 is deterministic — the same input always yields the same UUID. NIL is the all-zero placeholder.
What's the difference between v4 and v7?
Both are effectively unique, but v4 is fully random while v7 starts with a Unix-millisecond timestamp followed by random bits. That ordering matters: random v4 keys scatter across a database index and can hurt write performance, whereas time-ordered v7 keys are appended in order, keeping the index tidy. For new systems, v7 is increasingly the recommended choice.
What is a v5 UUID and when would I use it?
v5 is deterministic: it's the SHA-1 hash of a 'namespace' UUID plus a name you provide, so the same namespace and name always produce the exact same UUID. That's useful when you need a stable, reproducible ID for something — for example, deriving a consistent identifier from a URL or filename without storing a lookup table.
Are these UUIDs cryptographically random?
Yes for the random parts — they use the browser's Web Crypto API (crypto.randomUUID and getRandomValues), the same cryptographically secure generator used for security-sensitive work, not the weaker Math.random(). That said, a UUID is an identifier, not a secret; don't use one as a password or security token on its own.
Can two UUIDs ever be the same?
In practice, no. A v4 UUID has 122 random bits — about 5.3 × 10³⁶ possibilities. You'd have to generate roughly a billion UUIDs every second for around 85 years to reach even a 50% chance of a single collision. For any normal application, treating them as unique is completely safe.
Is this generator private?
Completely. Every UUID is created in your browser; nothing is requested from or sent to a server, and nothing is stored. You can generate as many as you like, offline, and none of them are logged or shared.