Generate unique UUID v4 identifiers instantly. Cryptographically secure with bulk generation and multiple format options. All processing happens locally in your browser.
Select how many UUIDs you need to generate at once. Options range from 1 to 100 for bulk generation needs.
Choose your preferred format: lowercase (default), uppercase, or with braces (commonly used in Windows/.NET environments).
Click "Generate" to create your UUIDs. Copy individual UUIDs with the copy button, or use "Copy All" to copy all generated UUIDs at once.
Use the validation section to check if an existing string is a valid UUID v4. Paste any UUID and click "Validate" to verify its format.
A UUID is a 128-bit value displayed as 32 hexadecimal digits in 5 groups separated by hyphens: 8-4-4-4-12. For example: 550e8400-e29b-41d4-a716-446655440000. The format is standardized in RFC 4122.
Uses 122 bits of random data for uniqueness. Position 13 is always "4" (version identifier). Position 17 is 8, 9, a, or b (variant identifier). All other positions are random hexadecimal digits. No timestamp or MAC address information.
This tool uses the Web Crypto API (crypto.randomUUID()) which internally uses a cryptographically secure random number generator. The browser generates 122 random bits, then sets the version (4) and variant bits according to RFC 4122.
With 2^122 possible UUIDs, the probability of collision is negligible. To have a 50% chance of collision, you would need approximately 2.71 quintillion UUIDs. Generating 1 billion UUIDs per second would take about 86 years to reach that point.
UUID v4 is unpredictable and suitable for security use. Cannot be guessed or enumerated. No information leakage (unlike v1 with MAC address). Safe for session IDs, API keys, and secret tokens. Generated locally - never sent to any server.
Auto-increment IDs: Predictable, expose record count, not portable. Timestamps: Can collide, expose creation time. Random numbers: Need length consideration, format varies. UUID v4: Standardized, portable, unpredictable, collision-resistant.
UUID (Universally Unique Identifier) is a 128-bit identifier that is practically guaranteed to be unique across all space and time. UUIDs are commonly used in databases, distributed systems, and applications where unique identifiers are needed without central coordination.
Saved Presets is a Supporter feature.
Tool History is a Supporter feature.
Tool Notes is a Supporter feature.
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