UUID generator
Generate unique identifiers in the format you need: UUIDs of any version, ULIDs, or NanoIDs, with secure random generation.
From 1 to 1,000
The same name always gives the same UUID.
From 1 to 1,000
A ULID is 26 characters long, starts with the date in milliseconds, and sorts alphabetically.
From 2 to 128
From 1 to 1,000
Between 2 and 256 distinct characters.
With the focus on the result, press Space or Enter to generate more.
Output format
Accepts UUIDs with or without hyphens, with braces or with “urn:uuid:”, and ULIDs.
Paste an identifier to see its version, variant, and date.
How to use it
- Choose the type of identifier: UUID, ULID, or NanoID.
- Adjust the version and the count, from 1 to 1,000. For v3 and v5, enter the namespace and the name.
- Change the format if you need to: uppercase, no hyphens, with braces, or as a JSON array.
- Press “Generate more” or the space bar to get new values, then copy the result or download it as TXT, CSV, or JSON.
- To check an identifier you already have, go to “Analyze” and paste it: you will see its version, variant, and creation date.
Frequently asked questions
What is the difference between a UUID and a GUID?
They are the same thing. GUID is the name Microsoft uses for the 128-bit identifier that the RFC 9562 standard calls a UUID. For the format with braces, typical of .NET and Windows, choose “Braces { }” in the output format.
Which UUID version should I use?
v4 is the most widely used and works almost every time: it is pure randomness. v7 starts with the date and sorts by creation time, which makes it better as a primary key in databases. v5 is useful for always getting the same UUID from a name.
Can two v4 UUIDs be the same?
In theory yes, in practice no. A v4 UUID has 122 random bits, so you would need about 2.7 quintillion identifiers to have a 50% chance of a single collision.
Are the UUIDs generated securely?
Yes. We use crypto.getRandomValues, your browser’s cryptographic generator, and everything happens on your device. No identifier is sent to or stored on a server.
What are ULID and NanoID?
A ULID is 26 characters long, starts with the date in milliseconds, and sorts alphabetically. A NanoID is a random string shorter than a UUID (21 characters by default) with an alphabet you can customize. Both are safe to use in URLs.
Does a v1 UUID reveal anything about my computer?
It reveals the date and time of creation. The node at the end is random, not your MAC address, so it does not identify your computer. If you do not need the date, use v4.
What is a UUID
A UUID (universally unique identifier) is a 128-bit number written as 32 hexadecimal digits separated by hyphens, for example 550e8400-e29b-41d4-a716-446655440000. It is used to identify records, files, or sessions without needing a central server to hand out numbers.
UUID versions
- v1: combines the date and time with a node. It reveals when it was created.
- v3 and v5: calculated from a namespace and a name with MD5 (v3) or SHA-1 (v5). The same pair always gives the same result.
- v4: random. It is the most common version.
- v7: starts with the date in milliseconds and ends with randomness. It sorts by creation time and works very well as a database key.
UUID, ULID, and NanoID
ULID and NanoID solve the same problem in a different form: they are shorter and URL-friendly. ULID keeps date order; NanoID prioritizes brevity and lets you choose the alphabet.
Updated on September 29, 2026