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UUID generator

Make one or more UUIDs (called GUIDs in the Microsoft world) in one click. Choose version 4 or version 7, upper case, no hyphens or curly braces. Up to 1,000 at once, ready to copy or download.

Version

How it works

  1. Choose your settings

    The number and, for passwords, the length and which characters are allowed.

  2. Ready at once

    Every change gives a new set. Click Generate new for another one.

  3. Copy or download

    Copy everything, only the first, or save the list as a text file.

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit ID, written as 32 hexadecimal characters in five groups: 8-4-4-4-12, for example 0a9f4cf0-484c-4577-a6a2-d32179d83d79. The chance of two random UUIDs being equal is so small that you can create them anywhere without a central counter, for example as a database key, a file name or a request ID in log files.

Version 4 or version 7?

  • Version 4 is completely random: 122 random bits, the other six mark the version and variant. The most widely used kind.
  • Version 7 (RFC 9562) starts with the time in milliseconds, followed by random bits. New IDs sort in the order they were made, which is why this tool sorts its list when you choose it.

The time is the first 48 bits, the first twelve hexadecimal characters. A version 7 UUID that starts with 01a0fde2-7f1d was made on 2 October 2026 at 18:31 UTC: read that number as milliseconds since 1 January 1970 (1,790,965,874,461) and a timestamp converter shows the date. The first eight characters change only about once a minute, 65.5 seconds to be exact, so UUIDs made close together share a prefix. The price is that anyone can read the creation time from the ID.

Options

  • Number, from 1 to 1,000.
  • Version 4 (random) or Version 7 (sortable by time).
  • Upper case, Without hyphens and In curly braces {…}, which you can combine: {01A0FDE27FEC71FCA4001A8756695673}.
  • Generate new makes a new set; Download .txt saves the list as uuids.txt.

Both versions are made with crypto.getRandomValues in your browser. Need a password instead of an ID? Use the password generator, or fill test records with the JSON test data generator.

Frequently asked questions

Is a UUID the same as a GUID?

In practice, yes. GUID is the name Microsoft uses, and the text form is the same: 32 hexadecimal characters in groups of 8-4-4-4-12. Windows tools often show it in curly braces, which is what *In curly braces {…}* gives you, and in upper case, which *Upper case* gives you.

Can two UUIDs ever be the same?

In theory, but not in practice. A version 4 UUID has 122 random bits. You would need to make about 2.7 × 10¹⁸ of them, which is a billion a second for 86 years, to have a 50% chance of one repeat.

How do I recognise the version?

Look at the first character of the third group: it is `4` for version 4 and `7` for version 7. The first character of the fourth group is always `8`, `9`, `a` or `b`; that marks the standard variant.

Which version should I use as a database key?

Version 7, if the database keeps an index in order, because new IDs always land at the end instead of all over the index, which keeps inserts fast in big tables. Use version 4 if the ID must not reveal when the record was made.

Are the UUIDs uploaded or stored?

No. They are made on your device with `crypto.getRandomValues` and exist only in the box on this page. Nothing is sent anywhere.