UUID Generator
Generate one or many random version 4 UUIDs (GUIDs) right in your browser.
Runs entirely in your browser. Nothing you generate is ever uploaded.
How to use this tool
Pick how many UUIDs you need in the count box, choose lowercase or uppercase output, and press Generate. The results appear in the text area below, one UUID per line. Use the Copy button to grab them all at once, then paste them into your code, database seed, or config file. To make a fresh batch, just change the count and press Generate again.
How it works
This is a version 4 UUID, which means it is built almost entirely from random
data rather than from your machine address or the time. The format is 32 hexadecimal
characters split into five groups separated by dashes, for example
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. The digit that is always
4 marks the version, and the y position is restricted to
one of 8, 9, a, or b to mark the
variant. The generator uses the browser's built-in crypto.randomUUID(),
which draws from a cryptographically strong random source, so the values are
effectively unique without contacting any server.
A real example
Say you are seeding a test database and need three unique row identifiers. Set the count to 3, leave the case on lowercase, and press Generate. You might get output like:
Each line is a separate UUID. Switch the case selector to uppercase and press
Generate again if your style guide stores GUIDs in capitals, such as
3F2504E0-4F89-41D3-9A0C-0305E82C3301.
Common questions
What is the difference between a UUID and a GUID?
They are the same thing. GUID (globally unique identifier) is the name Microsoft uses, while UUID (universally unique identifier) is the term in the broader standard. Both describe the same 128-bit identifier, so a v4 UUID and a v4 GUID are interchangeable.
Are these UUIDs guaranteed to be unique?
Not guaranteed in the strict mathematical sense, but the odds of a collision are astronomically small. A version 4 UUID has 122 random bits, so you would need to generate billions of them before a duplicate becomes even slightly likely.
Can I generate UUIDs in bulk?
Yes. Set the count box to any number from 1 up to 1000 and press Generate. Each UUID is placed on its own line so you can copy the whole batch and paste it wherever you need it.
Is this safe to use for real applications?
The values come from the browser's cryptographically strong random source, so they are suitable for general application identifiers, database keys, and similar uses. For security tokens that must resist guessing, follow your platform's dedicated token guidance as well.
Does anything get sent to a server?
No. Every UUID is created locally using your browser's built-in generator. The page never sends your data anywhere, so it works even if you go offline after loading it.