UUID Generator

Produced with your browser's cryptographic random number generator, so they are suitable for production identifiers.

How to use the uuid generator

Choose how many UUIDs you need.

Pick the format – lowercase, uppercase or without hyphens.

Click Generate and copy or download the list.

Why use the Convert Now uuid generator

Cryptographically random

Version 4 UUIDs from a secure random source.

Bulk generation

Up to 500 at a time.

Three formats

Lowercase, uppercase or hyphen-free.

Copy or download

Straight to clipboard or a .txt file.

What a version 4 UUID is

A UUID is a 128-bit identifier written as 32 hexadecimal characters in five hyphen-separated groups. Version 4 means almost all of those bits are random – 122 of them, with six reserved to mark the version and variant. The point is that anyone can generate one independently, with no central coordination, and be confident it will not collide with anyone else's.

How unique is unique

With 122 random bits there are about 5.3 × 10³⁶ possible values. To reach even a one-in-a-billion chance of a single collision you would need to generate around 100 trillion UUIDs. In practical terms, if your generator uses a proper cryptographic random source – as this one does – collisions are not a risk worth engineering around.

When not to use UUIDs

They are excellent as distributed identifiers and poor as clustered database primary keys: because v4 UUIDs are random, inserts land all over the index and fragment it, which hurts write performance on large tables. Options include using a UUID as an external identifier alongside an internal auto-increment key, or using a time-ordered format such as UUIDv7 or ULID when you need both uniqueness and insert locality.

Read the guide: How to Create a Strong Password (That You Can Remember)

Frequently asked questions

What is a UUID?

A universally unique identifier: a 128-bit value written as 32 hexadecimal characters, used to identify records without central coordination.

What is the difference between a UUID and a GUID?

None in practice. GUID is Microsoft's name for the same 128-bit identifier format.

Are these UUIDs really unique?

Effectively yes. Version 4 UUIDs have 122 random bits, so a collision is astronomically unlikely when generated from a cryptographic random source.

What is a version 4 UUID?

The random variant, as opposed to versions based on timestamps or MAC addresses. It is the most widely used type.

Can I use these in production?

Yes. They come from crypto.randomUUID or crypto.getRandomValues, both cryptographically secure.

Can I generate UUIDs without hyphens?

Yes – choose the "No hyphens" format option.