GUID Generator
Generate Globally Unique Identifiers (GUIDs). In Microsoft systems, GUIDs are equivalent to UUID v4.
Configuration
Generated UUIDs
Generate GUID
Definition
A GUID (Globally Unique Identifier) is Microsoft's implementation of a UUID. In practice, GUID and UUID (v4) are used interchangeably.
Format
GUID is typically displayed in braces:
{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
Or without braces:
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Structure
Microsoft GUIDs use UUID v4 format:
- Random bits: 122 bits of cryptographically secure random numbers
- Version: 4 bits set to 0100 (version 4)
- Variant: 2 bits set to 10 (RFC 4122 variant)
Worked example
A typical GUID:
{550e8400-e29b-41d4-a716-446655440000}
This is identical to a UUID v4. The "4" in the third group indicates version 4.
How to use
- Click "Generate" to create a new GUID
- Copy the result
- Repeat for multiple GUIDs
GUID vs UUID
| Aspect | GUID | UUID | |--------|------|------| | Origin | Microsoft | IETF (RFC 4122) | | Format | Often with braces | Standard hyphenated | | Implementation | Windows, .NET | Cross-platform | | Today | Typically v4 | Standard versions 1-8 |
Generating GUIDs
C#:
Guid.NewGuid()
JavaScript:
crypto.randomUUID() // v4
Python:
import uuid
uuid.uuid4()
SQL Server:
NEWID()
Advantages
- Globally unique: Extremely low collision probability
- Platform independent: Works across systems
- Cryptographically secure: Hard to predict
- Wide support: Available in all major languages
Common use cases
- Database primary keys
- COM object identifiers
- Registry keys
- Session IDs
- Any unique identifier requirement
FAQ
Is GUID the same as UUID? In modern usage, yes - both typically refer to UUID v4.
What's the difference? GUID is Microsoft's term; UUID is the IETF standard. The formats are identical.
Can I convert GUID to UUID? Yes, they're the same format. Just remove/add braces if needed.
How many GUIDs can I generate? Effectively unlimited: 2^122 possible values.
Is GUID truly unique? Practically yes. The collision probability is astronomically low.
Should I use GUID for security tokens? Yes, GUID (v4) is the standard for security tokens.
Are GUIDs sorted? No, v4 GUIDs are random and unsorted. Use v7 for time-ordered identifiers.
Can GUIDs be reversed? No, they're generated from random data. You cannot recover the generator from a GUID.