UUID Generator Online Tool

Generate UUIDs of different versions (v1, v3, v4, v5) with customizable options. Validate and format existing UUIDs.

Generation Options

UUID Output

Complete Guide to Using Our UUID Generator Tool

Generating UUIDs

  1. Select UUID version from the dropdown:
    • Version 4 (Random) - Default and most common
    • Version 1 (Time-based)
    • Version 3/5 (Namespace-based)
    • Custom pattern
  2. Configure version-specific options that appear
  3. Set quantity (1-1000 UUIDs at once)
  4. Copy results with:
    • Copy button
    • Standard Ctrl+C/Cmd+C

Validating & Formatting UUIDs

  1. Switch to "Validate/Format" mode from the version dropdown
  2. Paste UUIDs (one per line) to validate
  3. Choose formatting options:
    • Hyphenate output (default)
    • Remove hyphens
    • Uppercase conversion
  4. Invalid UUIDs are clearly marked in results

Supported UUID Versions

Version
Type
Use Case
Example Inputs
Version 1
Time-based
When you need temporal ordering
  • MAC: 00:1A:2B:3C:4D:5E (optional)
  • Clock Seq: 12345 (optional)
Version 3
MD5 hash
Deterministic UUIDs from names
  • Namespace: DNS, URL, etc.
  • Name: example.com, /path/to/resource
  • Custom NS: 550e8400-e29b-41d4-a716-446655440000
Version 4
Random
Most common, general purpose
No inputs required
Version 5
SHA-1 hash
Deterministic UUIDs (more secure than v3)
  • Namespace: DNS, URL, etc.
  • Name: user@domain.com, product-123
  • Custom NS: 550e8400-e29b-41d4-a716-446655440000

Detailed Usage Examples

Generating a UUID for a DNS name:
  1. Select Version 3 (MD5 Namespace) from dropdown
  2. Choose DNS from namespace dropdown
  3. Enter example.com in the Name field
  4. Click Generate
  5. Result: 9073926b-929f-31c2-abc9-fad77ae3e8eb
Generating a UUID for a URL path with custom namespace:
  1. Select Version 3 (MD5 Namespace)
  2. Choose Custom UUID from namespace dropdown
  3. Enter an existing UUID like 6ba7b811-9dad-11d1-80b4-00c04fd430c8 (URL namespace)
  4. Enter /products/widget-123 in the Name field
  5. Click Generate
  6. Result: c10626b2-9b6c-3a5b-9a43-0a2e05b0a1d3
Note: Version 3 UUIDs are deterministic - the same namespace and name will always produce the same UUID.

Generating a UUID for an email address:
  1. Select Version 5 (SHA-1 Namespace) from dropdown
  2. Choose URL from namespace dropdown
  3. Enter user@example.com in the Name field
  4. Click Generate
  5. Result: 5df41881-3aed-5145-9b6d-e0c2c7e5e5e5
Creating consistent IDs for database records:
  1. Select Version 5 (SHA-1 Namespace)
  2. Choose Custom UUID from namespace dropdown
  3. Enter your application's base UUID like 123e4567-e89b-12d3-a456-426614174000
  4. Enter a compound name like users:78432 (table:record_id)
  5. Click Generate
  6. Result: a3bb12e1-5c2f-5a4a-8f3d-3e7a4b5c6d7e
Tip: Version 5 is preferred over Version 3 when security is a concern, as it uses the more secure SHA-1 algorithm.

Version 1 (Time-based) Example:
  1. Select Version 1 (Time-based)
  2. Optionally enter a MAC address like 00:1A:2B:3C:4D:5E
  3. Optionally set a clock sequence number (0-65535)
  4. Click Generate
  5. Result: 2a3b4c5d-6e7f-11ed-8b9c-001a2b3c4d5e
Version 4 (Random) Example:
  1. Select Version 4 (Random)
  2. Set quantity if needed (default is 1)
  3. Click Generate
  4. Result: 550e8400-e29b-41d4-a716-446655440000

Key Technical Details

UUID Structure

  • 32 hex digits (16 octets)
  • Standard format: 8-4-4-4-12
  • Version digit: Indicates generation method
  • Variant bits: Ensures proper formatting
  • Namespace UUIDs (v3/v5):
    • First part is hash of namespace UUID
    • Second part is hash of your name string
    • Always produces same UUID for same inputs

Common Use Cases

  • Database keys: Unique record identifiers
  • Distributed systems: Conflict-free IDs
  • Session tokens: Secure random identifiers
  • File naming: Guaranteed unique filenames
  • Namespace UUIDs (v3/v5) are great for:
    • Generating consistent IDs from names/URLs
    • Creating predictable but unique identifiers
    • Mapping external resources to internal IDs

Best Practices

  • Version 4 is recommended for most use cases
  • Namespace UUIDs (v3/v5) are great for deterministic generation:
    • Use v3 when you need compatibility with older systems
    • Use v5 when security is a concern (SHA-1 is more secure than MD5)
    • Choose meaningful namespaces and names for reproducible results
  • Time-based UUIDs (v1) provide natural ordering
  • Validation is crucial when accepting UUIDs from external sources

Frequently Asked Questions

Version 4 (random) is suitable for most applications. Use Version 1 if you need time-based ordering, or Version 3/5 if you need to generate the same UUID repeatedly from a name/namespace. Version 5 is preferred over Version 3 when security is a concern.

Version 3 uses MD5 hashing while Version 5 uses SHA-1 hashing. The key differences are:

  • SHA-1 (v5) is more secure than MD5 (v3)
  • Version 5 UUIDs have better distribution characteristics
  • Version 3 is slightly faster to generate
  • Both produce the same UUID for the same inputs

For new applications, Version 5 is generally recommended unless you specifically need compatibility with systems using Version 3.

Yes, our tool generates standards-compliant UUIDs suitable for production use. All processing happens in your browser - no UUIDs are sent to our servers. For high-volume applications, consider implementing UUID generation directly in your application code.

Here are some common namespace examples:

  • DNS: For domain names (example.com)
  • URL: For web resources (https://example.com/path)
  • Email: For email addresses (use URL namespace)
  • Custom: For application-specific IDs:
    • users:78432 (table:record_id)
    • products:widget-123
    • orders:2023-45678

The namespace helps ensure your UUIDs won't collide with UUIDs generated from other namespaces.

Pro Tips

  • Use custom patterns when you need specific UUID formats
  • The validation tool can reformat existing UUIDs
  • For namespace UUIDs, document your namespace choices for consistency
  • Bookmark this tool for quick access during development
  • For v3/v5 UUIDs:
    • Standard namespaces (DNS, URL, etc.) have predefined UUIDs
    • You can create your own namespace UUIDs for different domains
    • The same inputs will always produce the same UUID