UUID / GUID Generator
Generate cryptographically random UUID v4 / GUID values in bulk and copy them with one click
Options
Generated UUIDs
Your generated UUIDs will appear here...
About this tool
The UUID generator creates random universally unique identifiers, also known as GUIDs, that developers use as primary keys, request IDs, file names and tokens. It produces version 4 UUIDs, which are built almost entirely from random bits, so two generated values practically never collide. You can create many at once, switch them to uppercase, strip the hyphens for a compact 32-character string, or wrap them in curly braces to match the Microsoft GUID registry form. Every value can be copied individually or all together. The whole tool runs in your browser using your device's cryptographically secure random source, so nothing is sent to a server.
How to use
- 1 Enter how many UUIDs you need; the field is capped at a safe maximum.
- 2 Pick your format: uppercase letters, no hyphens, or curly braces for GUID style.
- 3 Click Generate to create the list of random version 4 UUIDs instantly.
- 4 Use the copy button next to any UUID, or Copy all to grab the whole list at once.
How it works
A version 4 UUID is a 128-bit value written as 32 hexadecimal digits in the familiar 8-4-4-4-12 pattern, such as 3f50a1c2-9b6e-4d7a-8f12-ab34cd56ef78. Of those 128 bits, 122 are random and 6 are fixed to mark the version (4) and variant, which leaves about 5.3 x 10^36 possible values, so accidental duplicates are effectively impossible. This tool fills those random bits using the Web Crypto API, preferring crypto.randomUUID and falling back to crypto.getRandomValues, which are cryptographically secure rather than the predictable Math.random. The formatting options only change how the same value is displayed: uppercase, hyphen-free, or wrapped in braces.
Frequently asked questions
What is a UUID and is it the same as a GUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique across systems without a central authority. GUID (Globally Unique Identifier) is Microsoft's name for the same thing, often shown wrapped in curly braces. The values are interchangeable, so this tool generates both.
What is a version 4 UUID?
Version 4 is the random UUID variant. Almost all of its bits come from a random number source, with only the version and variant bits fixed. It needs no MAC address or timestamp, which makes it the most common choice for keys, tokens and request IDs.
Are these UUIDs safe to use as unique keys?
Yes. With 122 random bits there are over 5 x 10^36 possible values, so the chance of generating the same UUID twice is astronomically small. This tool uses your browser's cryptographically secure random generator rather than Math.random, so the values are unpredictable and well distributed.
What do the uppercase, hyphen and braces options do?
They only change formatting, not the underlying value. Uppercase shows the hex digits in capitals, removing hyphens gives a compact 32-character string, and braces wrap the value as {xxxxxxxx-...} to match the classic Microsoft GUID registry format.
Are the generated UUIDs sent anywhere?
No. Everything is generated locally in your browser, so no UUID is uploaded or stored on a server. The tool also keeps working offline once the page has loaded.
Related tools and uses
Pair the UUID generator with the hash generator when you need deterministic identifiers, the random generator for numbers and strings, and the Base64 or JSON tools when embedding IDs into payloads. Developers reach for UUIDs as database primary keys, API request IDs, idempotency keys and unique file names during prototyping and production alike.