UUID Generator

Generate and validate universally unique identifiers

Select UUID Version

Version 4 (Random) Recommended

Cryptographically random UUID. Best for general purpose use, databases, and unique identifiers.

Version 1 (Timestamp)

Based on timestamp and node ID. Useful when you need sortable UUIDs or temporal tracking.

Version 5 (SHA-1 Name-based)

Deterministic UUID from namespace and name. Same inputs always produce the same UUID.

Namespace Name (string to hash)

Number of UUIDs:

Format:

Uppercase No dashes

Output

Uses Web Crypto API for cryptographically secure random generation. All processing happens locally in your browser.

Component Breakdown

Validates UUID format, version, and variant according to RFC 4122 specification.

Batch Validation

All conversions preserve the original UUID value. Different formats are used by different systems and programming languages.

UUID Structure

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx | | | | | | | | | +-- Node (48 bits) | | | +-------------- Clock Seq (14 bits) | | +--------------------- Version (M = 1-5) | +---------------------------- Time Mid (16 bits) +-------------------------------------- Time Low (32 bits) M = Version (4 bits): 1 = Timestamp + MAC address 2 = DCE Security (rarely used) 3 = MD5 hash (namespace) 4 = Random <-- Most common 5 = SHA-1 hash (namespace) N = Variant (first 2-3 bits): 10xx = RFC 4122 (standard) 110x = Microsoft COM/DCOM 111x = Reserved for future

Version Comparison

Use Case	Recommended Version	Why
Database primary keys	Version 4	Cryptographically random, no collisions
Need temporal sorting	Version 1 or ULID	Timestamp is encoded in the UUID
Deterministic IDs	Version 5	Same input always = same UUID
Distributed systems	Version 4	No coordination needed between nodes
Content-based addressing	Version 5	UUID derived from content itself

Special UUIDs

NIL UUID 00000000-0000-0000-0000-000000000000

Max UUID ffffffff-ffff-ffff-ffff-ffffffffffff

Code Examples

                        JavaScript (Browser/Node.js 15+)
                        // Native UUID v4
const uuid = crypto.randomUUID();

// Or using Web Crypto API
function generateUUID() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
  );
}
                    

                        Python
                        import uuid

# Version 4 (random)
id = uuid.uuid4()

# Version 1 (timestamp)
id = uuid.uuid1()

# Version 5 (SHA-1 namespace)
id = uuid.uuid5(uuid.NAMESPACE_DNS, 'example.com')
                    

                        PostgreSQL
                        -- Enable extension
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

-- Generate v4 UUID
SELECT uuid_generate_v4();

-- Or use built-in (PostgreSQL 13+)
SELECT gen_random_uuid();
                    

                        C# / .NET
                        // Generate new GUID
Guid newGuid = Guid.NewGuid();

// Parse from string
Guid parsed = Guid.Parse("550e8400-e29b-41d4-a716-446655440000");

// Format options
string formatted = newGuid.ToString("D"); // With hyphens
string compact = newGuid.ToString("N");   // No hyphens
                    