Chmod calculator
Work out Unix file permissions.
UUID generator
Generate random UUIDs, version 4 or time-ordered version 7, in bulk.
Version 7 starts with a millisecond timestamp, so new IDs sort after older ones. Good for database keys.
Your files stay on your device
How it works
- 1Choose version 4 or version 7.
- 2Set how many IDs you need, up to 1000.
- 3Turn on uppercase, hyphens or braces to match your format.
- 4Copy the list or download it as a text file.
What the options do
- Version 4
- 122 random bits. The common choice when you only need a unique ID.
- Version 7
- Starts with the current time in milliseconds, so IDs sort in creation order. Friendlier to database indexes.
- Uppercase, hyphens, braces
- Formatting only. The underlying value is the same.
Privacy
This tool runs in your browser. Your files are never uploaded to a server.
Questions people ask
Can two UUIDs ever be the same?
In theory yes, in practice no. With version 4 you would need to generate billions per second for years before a collision becomes likely.
Are these random numbers secure?
They come from the browser's cryptographic random generator, the same source used for security tokens. Still, a UUID is an identifier, not a secret, so do not use one as a password or API key.
Which version should I choose for a database key?
Version 7 is usually better: because new IDs are larger than older ones, inserts stay near the end of the index. Version 4 spreads inserts at random across the index.
Does version 7 reveal when it was created?
Yes. The first 48 bits are a timestamp, so anyone can read the creation time. Use version 4 if that matters.
Is it a GUID?
GUID is the Microsoft name for the same 128-bit format. The braces option writes the form some Windows tools expect.