---
title: "UUID generator — free, runs in your browser"
description: "Generate random version 4 UUIDs in your browser. Free, no sign-up, and nothing you enter leaves your browser."
url: https://atoneplace.net/tools/uuid-generator/
site: "At One Place"
---

# UUID generator

Generate random version 4 UUIDs in your browser.

## How it works

A UUID is a 128-bit identifier written as 32 hexadecimal digits in five hyphenated groups. Version 4 UUIDs are random apart from six fixed bits that mark the version and variant, leaving 122 random bits.

The point of a UUID is that separate systems can generate identifiers independently and never collide, without coordinating. With 122 random bits, you would need to generate roughly 2.7 × 10¹⁸ of them before a collision became as likely as not — a number large enough that collision is not a practical concern.

These are generated with your browser's cryptographic random number generator and never leave your device.

> This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

## Common questions

### What is a version 4 UUID?

A UUID whose bits are random apart from six that identify the version and variant. It is the most commonly used kind because it needs no central coordination and no knowledge of the machine generating it.

### Can two UUIDs be the same?

In principle yes, in practice no. With 122 random bits you would need on the order of 2.7 × 10¹⁸ UUIDs before a collision became more likely than not.

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