UUID Generator

Generate secure UUID version 4 identifiers instantly for development, databases, testing and more.

Number of UUIDs

Format options

Uppercase

Remove hyphens from output

🔒 UUID v4 values are generated locally using browser cryptographic randomness.

Generate UUID v4 identifiers

Create one or many UUID version 4 values for application development, databases, test data and unique identifiers.

How UUID v4 works

A UUID v4 is a 128-bit identifier whose random bits are generated independently. The standard text format contains 32 hexadecimal digits separated by hyphens.

Browser-based generation

The generator uses the browser Web Crypto API and does not need to send generated identifiers to a server.

Recognize the UUID format

A standard UUID uses five hexadecimal groups of 8, 4, 4, 4 and 12 characters. For example, 550e8400-e29b-41d4-a716-446655440000 illustrates the layout only; generate a new value for your own record instead of reusing this example.

Choose the representation your application accepts

Select a quantity from 1 to 100, choose uppercase or hyphen-free text if needed, and press Generate UUIDs. Removing hyphens leaves 32 hexadecimal characters. Some APIs expect the hyphenated form, so check the receiving field.

Random UUIDs are useful for test records and identifiers. They are not a replacement for access checks or a database uniqueness constraint. A public record identifier does not prove permission to view a record. Use the JSON Formatter to prepare a sample payload containing your identifiers.

Frequently Asked Questions

What is a UUID v4?

UUID version 4 is a randomly generated 128-bit identifier commonly represented as hexadecimal characters with hyphens.

How many UUIDs can I generate?

You can generate up to 100 UUIDs at a time.

Can I remove UUID hyphens?

Yes. Enable the remove-hyphens option for a compact 32-character hexadecimal output.

Are UUIDs generated locally?

Yes. The tool uses browser cryptographic randomness and runs on your device.

How likely is a duplicate?

A version 4 UUID has 122 random bits. Using the birthday-problem formula:

UUIDs generated	Chance of any duplicate
1 billion	about 1 in 10¹⁹
1 trillion	about 1 in 10 trillion
2.7 × 10¹⁸	50%

At a billion UUIDs per second, reaching a 50% chance would take about 86 years. For database keys that should sort by creation time, version 7 is worth considering. See UUID Versions Explained.