UUID Generator (v4 & v7) – Bulk GUIDs up to 10,000

Bulk-generate up to 10,000 RFC-compliant UUID v4 or v7 identifiers, copy or download instantly.

Version 4 UUIDs are 122 bits of pure randomness with no order to them; version 7, the newer RFC 9562 format, spends 48 of its 128 bits on a millisecond timestamp instead, which is why a batch of v7 identifiers sorts chronologically as plain strings while a batch of v4 ones scatters randomly. The browser has a native crypto.randomUUID() for v4, but no equivalent for v7, so that half of the tool is hand-built to the RFC's exact bit layout.

How to generate UUIDs in bulk

  1. Pick UUID v4 (random) or UUID v7 (timestamp-ordered, sortable) from the Version menu.
  2. Enter a count between 1 and 10,000; anything above the cap is pulled back to 10,000.
  3. Set Hyphens (8-4-4-4-12 groups or 32 plain hex characters) and Case (lowercase or uppercase) first, because the format is applied as the batch is created.
  4. Click Generate, then Copy all, Download .txt, or Download .csv — the CSV adds a single uuid header line above the values.

What is a UUID (and a GUID)?

A UUID, or universally unique identifier, is a 128-bit value usually written as 32 hexadecimal digits in five hyphen-separated groups of 8, 4, 4, 4 and 12. It lets separate systems mint IDs without asking a central database for the next number. GUID, short for globally unique identifier, is the name Microsoft uses for exactly the same format, so a GUID generator and a UUID generator produce interchangeable values.

The first digit of the third group tells you the version. A 4 there means the value is almost entirely random; a 7 means it opens with a Unix timestamp in milliseconds followed by random bits. RFC 9562, published in 2024, defines both and replaced the older RFC 4122.

Where v7's extra structure comes from

A v7 identifier's first 48 bits are a big-endian Unix millisecond timestamp, followed by a 4-bit version field, a 12-bit random segment, a 2-bit variant field, and a final 62 bits of randomness. Because the timestamp occupies the leading bytes, comparing two v7 values as raw strings — or as bytes, which is what a database index actually does — orders them by creation time, the same way comparing two timestamps would.

That property matters most as a database primary key: new v4 rows insert at random positions across an entire index, which is expensive to maintain at scale, while new v7 rows land clustered at the end in roughly the order they were created, much closer to how an auto-incrementing integer key behaves.

Staying ordered inside the same millisecond

Date.now() only has one-millisecond resolution, so generating several v7 IDs back-to-back could easily land on the identical timestamp. RFC 9562's 'Monotonic Random' method handles this by incrementing the 12-bit random segment instead of re-randomizing it whenever the clock hasn't visibly advanced, which keeps consecutive IDs strictly ordered even within the same millisecond. If that counter overflows — 4,096 calls inside one millisecond, an edge case rather than a routine one — the timestamp is nudged forward by a millisecond so ordering never breaks.

Formatting and generating in bulk

Hyphens and letter case are formatting choices applied while each batch is generated; they change how a value is written, never its 128 bits. Because the format is fixed at that moment, switching a toggle afterwards doesn't rewrite a batch already on screen — click Generate again, which draws fresh IDs, to get the new style. A single batch is capped at 10,000 identifiers, and the results can be copied as a block or downloaded as a newline-delimited .txt or .csv file.

Generate UUIDs in code

The embedded timestamp is informative, not an audit trail

The millisecond baked into a v7 ID reflects whatever the generating machine's local clock read at that instant — it isn't verified against any external source and can't be trusted the way a signed timestamp would be. Treat it as a useful sort key, not as evidence of when something really happened, and don't assume IDs minted on two machines with even slightly skewed clocks will interleave in true wall-clock order when compared against each other.

Questions people ask about Bulk UUID/GUID Generator

Is a UUID guaranteed to be unique?
Not mathematically, but in practice yes. A v4 value has 122 random bits, so you would need to generate roughly 2.7 quintillion of them before the odds of a single duplicate reached one in two. A v7 value relies on its random bits only among IDs created in the same millisecond.
What's the difference between a UUID and a GUID?
Nothing structural: GUID is Microsoft's name for the same 128-bit identifier. Windows tools often show GUIDs in uppercase and sometimes wrapped in curly braces; pick Uppercase here and add the braces yourself if a registry file or config expects them.
Can I get UUIDs without hyphens or in uppercase?
Yes. Set Hyphens to Unhyphenated for 32 continuous hex characters and Case to Uppercase before clicking Generate. Both settings carry through to Copy all and to the .txt and .csv downloads, since they are applied to each value as it is created.
Are the UUIDs generated on a server?
No. Version 4 values come from your browser's crypto.randomUUID() and version 7 values from crypto.getRandomValues() plus your device clock, all inside this tab. The page makes no network request with the IDs, so they are yours alone the moment they appear.
Why would I choose UUID v7 instead of the far more common v4?
V7 embeds a millisecond timestamp in its leading bits, so values generated close together sort in creation order as plain strings or bytes. That makes it noticeably friendlier as a database primary key, since new rows cluster together in the index instead of inserting at random positions the way v4's fully random bits do.
Does embedding a timestamp make v7 leak more than v4 does?
It reveals the approximate millisecond the ID was created, which v4 never does. For most applications that's a minor trade against the indexing benefit, but if hiding creation time is a hard requirement — for a security token, say — v4's fully random bits are the safer default.
What's the maximum number of UUIDs I can generate in one batch?
10,000 per batch. Typing a larger count into the field pulls it back down to that limit, so every batch you generate stays within the cap instead of producing a partial or unexpectedly oversized file.
Can two v7 values generated in the same millisecond ever come out identical?
No — the generator's monotonic-counter logic increments the random segment on every call within an unchanged millisecond instead of drawing fresh randomness, which guarantees each successive ID differs from the last even when the clock hasn't visibly ticked forward yet.

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Content reviewed 2026-09-27.