UUID Version

UUID v1 Generator

Create version-1 UUIDs that embed the current time and a node ID. v1 is the original UUID format from RFC 4122 and is useful when you want time-orderable, unique values without coordination.

Time-based v1 (RFC 4122)60-bit timestamp + node IDNothing leaves your browser

Version

How many

Uppercase Hyphens Braces { }

Result

Generated locally with the Web Crypto API — nothing leaves your browser.

What Is UUID v1 Generator?

A UUID v1 is built from the current timestamp (100-nanosecond units since 1582) plus a 48-bit node identifier. The time component makes v1 values naturally sortable by creation order.
The version digit is 1 and the variant bits follow RFC 4122. Historically the node ID was the MAC address of the generating machine; modern generators use a random node to avoid leaking hardware identity.

How to generate

Set how many UUIDs you need (1–1000).
Toggle uppercase, hyphens and braces formatting.
Press Generate, then copy, copy all, or export as .txt/.csv.

Use Cases

Event and log identifiers where chronological order is valuable.
Distributed systems that want roughly time-sortable keys without a central clock.
Replacing auto-increment IDs exposed in public URLs (avoids leaking row counts).

Structure

Layout: time_low(32) - time_mid(16) - time_hi_and_version(16) - clock_seq(16) - node(48). The first three fields carry the timestamp, so sorting by string order approximates creation order.

How UUID v1 Generator Compares

UUID v1	Time + node; sortable by creation time
UUID v4	Fully random; no time information
UUID v7	Modern time-ordered with millisecond precision

Code Examples

JavaScript

const { v1 } = require('uuid');
const id = v1();  // e.g. '2ed6657d-badc-11d1-1234-001631e8b748'

Python

import uuid
id = uuid.uuid1()  # embeds host ID + timestamp

Frequently Asked Questions

Does UUID v1 leak my MAC address?

Classic v1 used the MAC, but modern implementations (including this page) substitute a random 48-bit node, so your hardware address is not exposed.

Why would I pick v1 over v4?

Choose v1 when you want values that sort by creation time and rarely collide even without randomness. For pure uniqueness with no time signal, v4 is simpler.

Can two v1 UUIDs collide?

Only if the same node generates two IDs within the same 100-nanosecond tick and the clock sequence does not advance — extremely unlikely in practice.