Free · No sign-up · Runs in your browser
UUID Generator
Generate RFC 4122 compliant UUIDs — version 1 (timestamp), version 4 (random) and version 5 (namespace + name) — one at a time or 500 in bulk. Format them, copy them, download them. Nothing leaves your device.
How it works
Three steps, no accounts, no uploads — the generator is plain JavaScript running on your machine.
v4 for random IDs, v1 when you want time-ordered keys, v5 when the ID must be reproducible from a name.
Uppercase, drop the hyphens, wrap in braces or add the urn:uuid: prefix. The preview updates live.
Copy one UUID from its row, copy all of them at once, or download the batch as a .txt file.
Configure
Your options stay visible while you iterate.
Version, quantity & formatting
Formatting
Generated locally — no network request.
Live format preview
updates as you change options3f2504e0-4f89-41d3-9a0c-0305e82c3301
- Case
- lowercase
- Separators
- hyphens
- Wrapper
- none
- String length
- 36
Generated UUIDs
Bulk output, copy all & download
Which UUID version should you use?
All three are RFC 4122 compliant and 128 bits wide. They differ in how those bits are produced.
Contains a 60-bit count of 100-ns intervals since 15 Oct 1582 plus a node identifier. Great when database insert order should follow the ID. The node field is randomised here, with the multicast bit set, because browsers cannot read your MAC address.
Best for: append-only tables, logs, per-request trace IDs.
122 random bits from crypto.getRandomValues() — the browser CSPRNG, not Math.random(). Collision odds are negligible: you would need roughly 2.7 × 1018 UUIDs to reach a 50% chance of one duplicate.
Best for: primary keys, API resource IDs, test fixtures, almost everything.
SHA-1 over the namespace UUID followed by your name, with the version and variant bits overwritten. Deterministic: the same namespace and name always produce the same UUID, on any machine, in any language.
Best for: idempotent migrations, content-addressed IDs, stable slugs.
What you get
Generate a whole batch in one click and paste it straight into a seed script or SQL insert.
Case, hyphens, braces and URN prefix — with a live preview so there are no surprises.
Per-row copy icons, a Copy all button, and a select-the-textarea fallback if the Clipboard API is blocked.
Zero network calls and zero storage. Nothing you type or generate ever leaves the browser tab.
Grab the whole batch as a newline-separated text file for fixtures, migrations and load tests.
Every page load runs an RFC 4122 self-test, including the canonical v5 vector for example.com.
FAQ
Are these UUIDs really random (v4)?
Yes. Random bytes come from the Web Crypto CSPRNG via crypto.getRandomValues(). Version 4 sets the version nibble to 4 and the variant bits to 10, exactly as RFC 4122 requires.
Do v1 UUIDs leak my MAC address?
No. Browsers do not expose the hardware address, so the node field is filled with random bytes and the multicast bit is set — the standard privacy-preserving substitute.
Why do v5 UUIDs need a suffix in bulk mode?
v5 is deterministic, so the same namespace and name always yield the same UUID. When you ask for a batch, the generator appends -1, -2, … to your name so every result is distinct.
Is there a batch or API limit?
500 UUIDs per click on desktop and 100 on small screens, so the list stays scannable and the page stays fast. 100 UUIDs typically render in well under 300 ms.
What if the clipboard is blocked?
Insecure contexts and some older mobile browsers block the Clipboard API. The tool then copies through a temporary textarea, or selects the bulk output and shows a “press Ctrl/Cmd+C” hint instead of failing silently.
Can I store UUIDs in a database column?
Yes — 36 characters as text, or 16 bytes in a native UUID type. Drop the hyphens and convert from hex if your schema stores binary UUIDs.