UUID generator
Generate unique identifiers: v4 (random) or v7 (sortable by date)
Version
Identifiers
Generate unique identifiers: v4 (random) or v7 (sortable by date)
About this tool
The UUID generator creates unique identifiers that follow RFC 9562, for primary keys, test fixtures, correlation IDs or file names. Choose version 4, which is fully random, or version 7, whose first characters encode the creation time in milliseconds, then generate anywhere from 1 to 500 identifiers in a single batch.
Two options shape the output to fit your needs: uppercase letters, and hyphens, which you can turn off to get a compact 32-character hex string. The random bytes come from crypto.getRandomValues, the browser's cryptographic random generator. The whole list copies in one go, one ID per line, ready to paste into a SQL script, a data file or a test.
How to use it
- Pick a Version: “v4 – random” or “v7 – sortable by date”.
- Set the Count of identifiers you need, from 1 to 500.
- Check “Uppercase” or uncheck “With hyphens” to match the format you expect.
- Click “Generate”, then “Copy all”.
Frequently asked questions
Should I use a v4 or a v7 UUID?
A v4 UUID is fully random and reveals nothing. A v7 UUID starts with its creation time, so IDs sort chronologically, which suits indexed database keys well. The trade-off is that anyone can read when a v7 UUID was created.
Are the generated UUIDs really unique?
A v4 UUID holds 122 random bits drawn with crypto.getRandomValues, so the odds of a duplicate are negligible even across billions of IDs. A v7 UUID combines a millisecond timestamp with 74 random bits, making a collision just as unlikely.
Can I generate more than 500 UUIDs at once?
No, the Count field is capped at 500 per run. To get more, click “Generate” several times: each click produces a fresh batch that replaces the previous one, so copy each batch before generating the next.
Are the identifiers created on a server?
No. They are generated in your browser, with no network request, and are not kept. Only your settings, meaning version, count, uppercase and hyphens, are saved locally for your next visit.