UUID Generator

What Is the UUID Generator?

The UUID Generator creates one or more UUIDv4 identifiers instantly, which are random 128-bit values formatted as a string of hexadecimal characters in the standard 8-4-4-4-12 pattern. You enter how many you want, click Generate, and they appear in the output ready to copy. UUIDs are used across software development for things like primary keys in databases, session tokens, file identifiers, and anywhere you need a unique ID that does not depend on a central authority to issue it.

UUIDv4 in particular is the version most people reach for in practice because it is entirely random, which makes it the least fussy to generate and good enough for nearly every common use case.

How to Use This Tool

1. Enter the number of UUIDs you want to generate in the quantity field. You can generate one or several at a time.
2. Click Generate and the tool produces that many random UUIDv4 values, each on its own line in the output area.
3. Copy all the generated UUIDs using the Copy button, or select and copy manually.
4. Click Generate again any time you need a fresh batch. Each click produces a completely new set of random values.

When Would You Use This?

Generating primary keys for new database records during development or testing, when you need unique identifiers before inserting data and want to assign them manually rather than relying on auto-increment.

Creating placeholder IDs for mock data, test fixtures, or seed files in a development environment where real identifiers have not been assigned yet but the data structure requires them.

Getting a quick unique string for naming a file, a configuration entry, an API resource, or anything else that needs a non-colliding identifier and where you do not want to think about what the value actually is.

Examples

Generating a single UUID

Quantity: 1
Output  : 3f6b2c84-1d47-4e9a-b531-7a2e90f4c618

Generating five UUIDs at once

Quantity: 5
Output  : a1b2c3d4-e5f6-4789-abcd-ef1234567890
9f8e7d6c-5b4a-4321-fedc-ba9876543210
1a2b3c4d-5e6f-4789-0abc-def123456789
f1e2d3c4-b5a6-4987-8765-432109876543
0a1b2c3d-4e5f-4678-9abc-def012345678
(Each click of Generate produces a completely new set of random values)

What a UUIDv4 looks like

Format  : xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
Example : 550e8400-e29b-41d4-a716-446655440000
(The 4 in the third group indicates version 4. The y position is constrained to 8, 9, a, or b)

Frequently Asked Questions

What is a UUID?

UUID stands for Universally Unique Identifier. It is a 128-bit value typically displayed as a 32-character hexadecimal string split into five groups by hyphens, like this: 550e8400-e29b-41d4-a716-446655440000. The format is standardized and widely supported across programming languages, databases, and systems.

What is UUIDv4?

UUIDv4 is the fourth version of the UUID standard and generates its value using random or pseudo-random numbers rather than based on a timestamp or hardware address. It is the most commonly used version because it is simple to generate and produces values that are statistically unlikely to collide even across large systems.

How do I generate a UUID in Python?

Import the uuid module and call uuid.uuid4(): import uuid; print(uuid.uuid4()). This returns a random UUIDv4 object which you can convert to a string with str(). For a quick batch of UUIDs without opening a code editor, this tool generates them in seconds.

How do I generate a UUID in JavaScript?

In modern browsers and Node.js you can use the built-in crypto.randomUUID() method. Older environments may require a library like the uuid package from npm. For quick generation without any code, use this tool.

Are UUIDs truly unique?

UUIDv4 values are not guaranteed unique in a strict mathematical sense, but the probability of generating two identical values is so low it is effectively impossible in any real-world application. The total possible number of UUIDv4 values is 2 to the power of 122, which is an extremely large number.

Can two UUIDs ever be the same?

In theory yes, in practice no. With proper random number generation, the odds of a collision are astronomically small. In any application generating millions of UUIDs, a collision is something you would not meaningfully need to worry about.

What is the difference between UUID and GUID?

They are the same thing. GUID stands for Globally Unique Identifier and is Microsoft's term for the same concept. The format and behavior are identical.

How long is a UUID?

A UUID is 32 hexadecimal characters plus 4 hyphens, for a total of 36 characters in its standard string form. Stored as raw bytes it is 16 bytes.

Can I use a UUID as a database primary key?

Yes, and it is a common pattern. UUIDs as primary keys make it easy to generate IDs before inserting records and work well in distributed systems where multiple nodes need to create records independently without coordinating on ID values. The trade-off is that UUID primary keys are larger than integer keys and can affect index performance in some databases.