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UUID Generator

Generate version 4 and version 7 UUIDs in bulk, with case and format options.

Version

Version 4 is fully random. Version 7 begins with the current time, so a batch sorts by creation order, which suits database keys. Nil is the all-zero placeholder value.

Choose how many to generate, from 1 to 1000.

Format

How to generate UUIDs online

  1. Choose a version

    Pick version 4 for fully random identifiers or version 7 for time-ordered ones that sort by creation order. A Nil option produces the all-zero placeholder value.

  2. Set the amount

    Enter how many UUIDs you need, anywhere from 1 to 1000. A batch appears as soon as the page loads and updates when the count changes.

  3. Adjust the format

    Toggle uppercase for systems that expect capital hex, turn off hyphens for the compact 32-character form, or add braces for consumers that expect them.

  4. Copy the batch

    Copy to clipboard grabs every UUID in the list, one per line. Regenerate rolls a fresh batch without touching your settings.

Why use this tool

Version 4 and version 7

Generate fully random version 4 identifiers, or version 7 ones that begin with a millisecond timestamp so a batch sorts by creation time. Both are drawn from your browser's cryptographically secure random source, with the version and variant bits set exactly as the spec requires.

Up to 1000 at a time

One field controls batch size, so seeding a database fixture or a spreadsheet column takes a single copy instead of a thousand clicks.

Case, hyphen, and brace formats

Switch every UUID between lowercase and uppercase, drop the hyphens for the plain 32-character hex form, or wrap each value in braces for consumers that expect them.

One-click reroll

Regenerate replaces the whole batch instantly while keeping your count and format settings.

Newline-separated output

The batch copies as one UUID per line, ready to paste into a script, a CSV column, or a test file.

Generated on your device

Values are created locally in the browser tab, not fetched from a service, so no one else ever sees them and there is no rate limit.

About this tool

This UUID generator produces version 4 (random) and version 7 (time-ordered) UUIDs drawn from your browser's cryptographically secure random source, with the version and variant bits set as the spec requires. A Nil option outputs the all-zero placeholder value. Set a count between 1 and 1000 and the batch regenerates automatically; the uppercase, hyphen, and braces toggles re-case and re-shape the existing list without rerolling it.

UUIDs turn up wherever things need names that cannot collide: primary keys in databases that do not auto-increment, correlation IDs threaded through logs and distributed traces, idempotency keys for payment APIs, filenames for uploads, and fixture data for tests. Bulk generation is the point here; needing one UUID is rare, and needing two hundred for a seed script is common.

Generation happens on your machine, which means the identifiers are not drawn from a shared server sequence and are never known to anyone but you. Version 4 UUIDs are pure randomness, carrying no embedded timestamp or machine address, so nothing about when or where one was made can be read back out of it. Version 7 instead front-loads a millisecond timestamp, which keeps the random uniqueness but lets a batch sort in creation order, a property that makes them a friendlier fit for database primary keys where random inserts would otherwise scatter across an index. If you need a deterministic fingerprint of existing content instead of a random ID, use the hash generator; for placeholder text to go with placeholder keys, there is the lorem ipsum generator.

Frequently asked questions

What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit value written as 32 hexadecimal digits in five hyphen-separated groups, like 123e4567-e89b-12d3-a456-426614174000. Version 4 UUIDs are random, so two generated independently are effectively guaranteed never to collide.
How are these UUIDs generated?
Version 4 and version 7 UUIDs are drawn from your browser's cryptographically secure random source, with the version and variant bits set as the spec requires. Generation happens entirely on your device, so no two people share a sequence and nothing is fetched from a server.
What is the difference between version 4 and version 7?
Version 4 is fully random, so its values carry no order or timestamp. Version 7 places a millisecond timestamp in the first bytes and fills the rest with randomness, so a batch generated over time sorts by creation order. That ordering makes version 7 a good fit for database primary keys, where fully random keys would scatter inserts across an index.
How many can I generate at once?
Set any count from 1 to 1000. The list updates instantly, and the Regenerate button rolls a fresh batch. Use the copy button to copy every UUID, one per line.
Can I get uppercase, hyphen-free, or braced UUIDs?
Yes. By default UUIDs are lowercase with hyphens. Toggle to uppercase for systems that expect it, turn off hyphens to get the compact 32-character form used by some databases and APIs, and add braces to wrap each value for consumers that expect the braced form.
Are the generated UUIDs sent anywhere?
No. Everything is generated locally in your browser. The values never leave your device, are never uploaded, and are not stored or logged.

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