What is the difference between a UUID and a GUID?

GUID (Globally Unique Identifier) is Microsoft's implementation of the standard UUID specification. They are functionally identical.

Updated: August 2026 • Verified v1.2

UUID / GUID Generator

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Generate cryptographically random UUID v4 and timestamp-based UUID v1 identifiers in bulk with uppercase, hyphen, and brace formatting.

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RFC 4122 UUID v4: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx (where y is 8, 9, a, or b)

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Understanding Your Results

A UUID v4 contains 122 bits of cryptographically random entropy. The collision probability across billions of generated IDs is practically zero.

Practical Guidance & Next Steps

Use Version 4 for distributed database primary keys and API idempotency keys. Toggle 'Uppercase' or 'Remove hyphens' based on your database or programming language conventions.

What is this?

A standard RFC 4122 compliant UUID (Universally Unique Identifier) / GUID generator producing 128-bit identifiers with near-zero collision probability.

How does it work?

1. Select UUID version (v4 Random or v1 Timestamp). 2. Choose quantity (1 to 500). 3. Set format preferences (hyphens, braces, uppercase/lowercase). 4. Click 'Generate' and copy individual UUIDs or all at once.

Why use it?

Essential for creating primary keys in distributed databases, unique transaction IDs, session tokens, and tracking identifiers.

Technical Scope & Calculation Limitations

UUID v4 is randomly distributed and non-sequential; for high-write B-tree database indexing where sequential insertion order is required, UUID v7 or ULID is recommended.