How to use UUID Generator
- Copy the UUID at the top, or tap New for another. Switch to v7 for ids that sort by time.
- Set upper case, no hyphens or braces to match what your system expects.
- Type how many you need (up to 1,000), pick Lines, JSON, SQL or CSV, and Copy or Download.
- Paste a UUID into Check to see its version and variant, and the time a v1 or v7 id was made.
Why use UUID Generator
Truly random
v4 ids come from the browser's cryptographic random source (crypto.randomUUID), never Math.random.
v7 for databases
Time-ordered ids (RFC 9562) that index well as primary keys; a counter keeps ids made in the same millisecond in order.
Ready to paste
Lines for a text file, a JSON array for fixtures, a quoted SQL list for IN (…) and INSERT, CSV for a spreadsheet.
Checker
Says whether a string is a valid UUID, which version and variant it is, and when a time-based one was created.
About this tool
A UUID (GUID on Windows) is a 128-bit identifier written as 32 hex digits in five groups. Version 4 is random, and with 122 random bits the chance of two colliding is negligible, which is why it is the default for keys, file names and test data. Version 7, standardised in 2024, puts the time in the first 48 bits so ids sort by creation, which databases index far better than random ids.
This generator makes both in your browser from its secure random source, formats them the way different systems want (upper case for SQL Server, no hyphens for some APIs, braces for .NET), and produces up to a thousand at once. The checker reads the version and variant bits of any UUID and decodes the timestamp of a v1 or v7.
Frequently asked questions
What is the difference between a UUID and a GUID?
None in practice: GUID is Microsoft's name for the same 128-bit identifier. .NET writes it in braces by default, hence the braces option.
v4 or v7?
v4 when the id only needs to be unique. v7 when it will be a database primary key or you want ids to sort by creation time; it leaks the creation time, which is usually fine.
Are the UUIDs unique?
Each is drawn from 122 random bits (v4) or the time plus 74 random bits (v7). You would need to generate billions per second for centuries before a repeat became likely.
Can I generate more than 1,000?
Generate 1,000, copy, and repeat; the limit keeps the page quick. For millions, generate them in your own code with the same crypto.randomUUID call.
Are the ids stored or sent anywhere?
No. They are made in your browser and forgotten when you leave.