# UUID Generator

> Free UUID v4 generator. Create single or bulk random UUIDs with crypto-grade randomness, copy with one click. Everything runs in your browser.

Generate version 4 UUIDs instantly, one at a time or in bulk up to 100. Uses your browser's cryptographic random number generator, with one-click copy per UUID.

*Interactive tool: enter your values at https://toollantern.win/uuid-generator/ and results update instantly in your browser.*

## What the tool does

A UUID (universally unique identifier) is a 128-bit label like 3f6d4a8e-1c2b-4d5e-8f9a-0b1c2d3e4f5a, used for database keys, session IDs and filenames. Version 4 means fully random. This tool generates them with crypto.getRandomValues(), the browser's cryptographic RNG.

## Worked example

Click "Generate one" to get something like 9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d. Set the count to 10 and click Generate for ten at once, then Copy all to paste them into a spreadsheet.

## Collision odds

With 122 random bits, the chance of two v4 UUIDs colliding is effectively zero: you would need to generate billions per second for a century to expect one duplicate.

## Frequently asked questions
### What is a UUID?

A 128-bit identifier written as 32 hex digits in five groups, like 123e4567-e89b-12d3-a456-426614174000. It is designed to be unique without a central registry.

### What does version 4 mean?

The version digit (the first digit of the third group) tells how the UUID was made. Version 4 means randomly generated, the most common kind for application IDs.

### Are these UUIDs cryptographically random?

Yes. They come from crypto.getRandomValues(), the browser's cryptographic random number generator, not Math.random().

### Can two UUIDs be the same?

In theory yes, in practice no. With 122 random bits you would need about 2.7 quintillion UUIDs to reach a 50% collision chance.

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Interactive version: https://toollantern.win/uuid-generator/