UUID Generator
Generate RFC 4122 compliant Version 4 UUIDs (Universally Unique Identifiers) or GUIDs. All calculations are executed client-side using hardware-level random entropy.
Generation Settings
What is a Version 4 UUID / GUID?
Universally Unique Identifier
A Universally Unique Identifier (UUID) or Globally Unique Identifier (GUID) is a 128-bit value used to uniquely flag records across distributed computing systems. Version 4 UUIDs are entirely random. Out of 128 bits, 6 bits are reserved for variant and version attributes, leaving 122 bits of random generation.
Negligible Collision Probability
With 122 bits of random entropy, there are $2^122$ (roughly $5.3 \times 10^36$) possible Version 4 UUIDs. The probability of a collision (generating the same ID twice) is mathematically negligible — so small that even if you generated 1 billion UUIDs per second for 100 years, the risk of a single collision is practically zero.
How to Use UUID / GUID Generator
Select Quantity
Choose how many UUIDs to generate in bulk (from 1 up to 1,000 unique keys).
Customize Formatting
Select uppercase vs lowercase characters, hyphen inclusion, and quotes.
Cryptographic Generation
Operating system hardware randomness (`crypto.getRandomValues`) generates unguessable UUIDs.
Copy or Download List
Copy generated UUIDs to clipboard or export as a text file.
Key Features & Capabilities
- RFC 4122 compliant v4 random UUIDs
- Hardware cryptographic randomness (`crypto.getRandomValues`)
- Bulk generation up to 1,000 keys per batch
- Uppercase / lowercase & brace formatting
- 100% private offline browser generation
100% Client-Side Privacy: All operations occur locally in your web browser memory using JavaScript and WebAssembly. Your files, text payloads, and images are never uploaded to external servers or stored in cloud databases.
Frequently Asked Questions
View All Platform FAQsWhat is a UUID v4?
A Universally Unique Identifier (UUID) version 4 is a 128-bit number generated from cryptographically secure random bytes, conforming to RFC 4122 specifications.
What is the probability of a UUID v4 collision?
The collision probability is astronomically small. You would need to generate over 1 billion UUIDs per second for 85 years before having a 50% chance of a single duplicate key collision.
Experiencing an issue with UUID / GUID Generator?
Notice a bug, calculation error, or unexpected result? Let us know.