UUID/GUID Generator
Generate random UUID v4 or time-ordered UUID v7 in batches of up to 100, as hyphenated, plain, braced or URN strings, with copy and TXT download.
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Your UUIDs will appear here
On this page
Generate RFC 9562 UUIDs in your browser: random version 4 or time-ordered version 7, one at a time or up to 100 per batch. Choose hyphenated, plain, braced or URN output in lower or upper case, then copy a single ID, copy all, or download them as a text file.
Detailed Functionality
Version 4 fills 122 bits with random data from the browser's cryptographically secure generator (Web Crypto getRandomValues); the remaining six bits mark the version and variant. Version 7 starts with a 48-bit Unix timestamp in milliseconds, followed by a 12-bit counter and 62 random bits. The counter follows RFC 9562 §6.2: IDs created within the same millisecond — or after the system clock moves backwards — still increase strictly, so a batch of v7 UUIDs sorts in creation order. That makes v7 a good primary key for B-tree indexes, while v4 reveals nothing about when it was created.
Four output formats are available: the canonical hyphenated form 8-4-4-4-12, 32 hex digits without hyphens, braces {…} as used for GUIDs in Windows and .NET, and the URN urn:uuid:…. UPPERCASE changes only the hex digits; the URN prefix stays lower-case.
Generation runs entirely in JavaScript on the page — no WebAssembly and no server request — so the IDs never leave your device. The download is a plain .txt file with one UUID per line.
Practical Examples
Database key: version 4 in the hyphenated format gives values like xxxxxxxx-xxxx-4xxx-Yxxx-xxxxxxxxxxxx, where the 13th hex digit is always 4 and Y is 8, 9, a or b.
Sortable IDs: a v7 UUID created at 2023-11-14T22:13:20Z (Unix 1700000000000 ms) starts with 018bcfe5-6800-7 — the first 12 hex digits are the timestamp, so a batch sorts by time.
.NET / registry style: the Braces format with UPPERCASE produces {9F2C…}-style GUIDs ready to paste into C# attributes or .reg files.
Test fixtures: set the count to 100, generate a batch and use Download as TXT to get a file with 100 lines.
How to Use This Tool
Choose the version
Under UUID Version, pick Version 4 (Random) or Version 7 (Timestamp-based).
Set format, case and count
Select the Format and Case, and move the Number of UUIDs slider (1–100).
Generate
Press Generate; each press replaces the list with a new batch.
Copy or download
Copy a single UUID with the button in its row, use Copy All for the whole list, or Download as TXT to save it as a file.
Tips and Best Practices
- Use v7 for database primary keys and log correlation IDs: time ordering keeps index inserts local and makes IDs roughly sortable.
- A v7 UUID exposes its creation time to the nearest millisecond; use v4 where that must stay private.
- UUIDs are unique identifiers, not secrets — do not use them as passwords or session tokens.
- Most parsers accept either case, but RFC 9562 recommends lower case for output; UPPERCASE is for systems such as the Windows registry.
- The 32-digit plain form fits columns like
CHAR(32); store UUIDs as a native 16-byte type where your database has one.