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UUID Generator (GUID Tool) - v1, v4, v7
Create standard RFC 4122 UUIDs and GUIDs. Supports all versions including random (v4), time-based (v1, v6, v7), and namespace-based (v3, v5). Bulk generate, format, and copy instantly.
What is UUID Generator?
A UUID Generator is a developer tool that creates Universally Unique Identifiers (UUIDs), which are 128-bit labels used to uniquely identify information in computer systems without a central authority. This tool generates standard RFC 4122 compatible UUIDs, including random (v4) and time-ordered (v7) versions, locally in your browser.
How to Use UUID Generator
Key Features
All UUID Versions: Generate v1, v3, v4, v5, v6, and v7 UUIDs
Bulk Generation: Create up to 50 UUIDs at once
Python/Java Compatible: Generated IDs work seamlessly with standard libraries
Namespace Support: Presets for DNS, URL, OID, X.500 for v3/v5
Secure: All UUIDs are generated locally in your browser
One-Click Copy: Instantly copy generated IDs to clipboard
Latest Standards: Includes support for new time-ordered UUID v7
About UUID Generator
💡 Pro Tip: Database Performance
If you are using UUIDs as Primary Keys in a database (like PostgreSQL or MySQL), consider using UUID v7 instead of v4. UUID v7 is time-ordered (sortable), which significantly reduces index fragmentation and improves query performance compared to completely random v4 UUIDs.
UUID Version Comparison
| Version | Type | Best Use Case | Sortable? |
|---|---|---|---|
| v4 | Random | General unique IDs, Session IDs | No |
| v7 | Time-ordered | Database Keys, High-load systems | Yes |
| v1 | Time + MAC | Legacy systems requiring time | Partially |
| v3 / v5 | Namespace | Deterministic IDs from names | No |
How to Generate UUIDs in Code
Python
import uuid
# Generate random UUID (v4)
random_id = uuid.uuid4()
print(random_id)JavaScript / Node.js
// Modern Browsers & Node.js 19+
const uuid = crypto.randomUUID();
console.log(uuid);
// Using uuid package (npm install uuid)
import { v4 as uuidv4 } from 'uuid';
console.log(uuidv4());Java
import java.util.UUID;
UUID uuid = UUID.randomUUID();
System.out.println(uuid.toString());Understanding UUID Versions
- v1 (Timestamp): Generated from the current time and MAC address. Guaranteed unique per machine.
- v3 (MD5 Namespace): Deterministic UUID generated from a namespace and name using MD5 hashing.
- v4 (Random): Generated using random numbers. Most widely used version, recommended for 99% of general use cases.
- v5 (SHA-1 Namespace): Similar to v3 but uses stronger SHA-1 hashing.
- v6 (Reordered Time): Like v1 but optimized for database sorting.
- v7 (Unix Epoch): Modern time-based UUID, highly recommended for databases as primary keys.
Frequently Asked Questions
How can I generate a UUID?
You can generate a UUID instantly using our free online tool. Simply select the version you need (v4 is recommended for most random use cases) and click 'Generate'. Alternatively, in programming languages like Python, you can use `import uuid; uuid.uuid4()`.
What is UUID and why is it used?
UUID stands for Universally Unique Identifier. It is used to assign a unique ID to a record/resource without checking a central database. This is crucial for distributed systems where multiple servers create data simultaneously, preventing ID collisions.
Are these UUIDs unique?
Yes, standard UUIDs (like v4) have an extremely low probability of collision (1 in 2^122). For all practical purposes in software systems, they are considered globally unique.
Which UUID version should I use?
Use **UUID v4 (Random)** for general uniqueness. Use **UUID v7** for database primary keys because it is time-ordered (sortable), which improves database indexing performance. Use v3/v5 for deterministic IDs based on names.
Is it safe to share UUID?
Yes, UUIDs are generally safe to share as they are identifiers, not secrets (like passwords). However, v1 UUIDs contain your MAC address, which could affect privacy. v4 and v7 are completely safe to share.
What can I do with a UUID number?
You can use a UUID number as a primary key in databases (PostgreSQL, MySQL, MongoDB), as a unique session ID for users, for tracking transactions in distributed systems, or for naming files uniquely to prevent overwrites.