UUID v4 & v7 Generator Online - Free Universal Unique ID Tool
Generate UUID v1 (timestamp-based) and v4 (random) instantly. Bulk generation up to 100, multiple formats. 100% browser-based, privacy safe.
UUID Structure:
xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
time_low
time_mid
version
variant
node
M = version (1/4/7), N = variant (8/9/a/b for RFC 4122)
UUID Bit Layout by Version
| Version | Bit Layout | Source | Use Case |
|---|---|---|---|
| v1 | time_low(32)-time_mid(16)-ver(4)-clock_seq(12)-node(48) | Timestamp + MAC address | Time-ordered, database-friendly |
| v4 | random(48)-ver(4)-random(12)-variant(2)-random(62) | 122 random bits | General purpose, most common |
| v7 | unix_ts_ms(48)-ver(4)-rand(12)-variant(2)-rand(62) | Unix ms timestamp + random | Time-sortable, DB index friendly |
| v5 | name_based(48)-ver(4)-namespace(12)-variant(2)-hash(62) | SHA-1 hash of namespace + name | Deterministic IDs from names |
UUID Validator
Enter a UUID to validate and get detailed information about its version and structure.
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Key Features
Multiple Versions
Generate UUID v1 (timestamp-based), v4 (random), and v7 (time-ordered).
Bulk Generation
Generate up to 100 UUIDs at once for testing and development.
Easy Copy
Copy individual UUIDs or all generated UUIDs with one click.
Privacy Protected
All generation happens locally in your browser. No data leaves your device.
Frequently Asked Questions
Getting Started
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122, used to uniquely identify information in computer systems. It is typically represented as a 36-character string in the format 8-4-4-4-12 hex digits.
What is the difference between UUID v1 and v4?
UUID v1 is time-based, generated from the current timestamp and device MAC address. UUID v4 is random-based, using 122 bits of randomness from a cryptographically secure generator, providing stronger privacy and unpredictability.
Which UUID version should I use?
For most modern applications, UUID v4 (random) is recommended due to its simplicity and privacy. Use UUID v1 when you need time-based sorting. For database primary keys, consider UUID v7 for better index locality.
Is this UUID generator safe?
Yes, all operations run locally using crypto.getRandomValues(). No data is ever sent to any server. Generated UUIDs never leave your device.
Using the Generator
How do I generate UUIDs?
Select your preferred version, choose the quantity, pick your format, and click "Generate UUIDs". Results appear instantly in the output area below.
Can I generate multiple UUIDs at once?
Yes, you can generate up to 100 UUIDs in a single batch. Results display as a list, and you can copy all at once using the "Copy All" button.
What formats are available?
Standard with dashes, without dashes, uppercase, and uppercase without dashes. Output formats include one-per-line, comma-separated, JSON array, and SQL IN.
Can I generate UUIDs in different formats?
Yes! Our tool supports multiple output formats including standard with dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx), without dashes (xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx), uppercase, and uppercase without dashes. You can also choose output formatting options like one per line, comma-separated, JSON array, or SQL IN format for easy integration into your code.
What is the difference between UUID v4 and v7?
UUID v4 generates completely random identifiers (122 bits of randomness), while UUID v7 incorporates a Unix timestamp (milliseconds) in the first 48 bits followed by random bits. v7 offers time-ordered sorting benefits, making it ideal for database indexes (B-tree friendly). v4 is better when you need pure randomness and no time-based predictability.
Can UUIDs be generated in browsers and Node.js?
Yes! Our tool uses the Web Crypto API (crypto.getRandomValues) for browser-based generation, which is cryptographically secure. For Node.js, you can use the built-in uuid package: npm install uuid, then const { v4 } = require("uuid"); console.log(v4()); Our tool generates the same standards-compliant UUIDs that work across all platforms.