What is a UUID and what does it stand for?

UUID stands for Universally Unique Identifier. It's a 128-bit identifier that is unique across space and time, formatted as xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (36 characters with hyphens). Also known as GUID (Globally Unique Identifier) in Microsoft systems.

How do I generate a UUID online?

Select your desired UUID version (v1, v4, v5, or v7), set the quantity for bulk generation, and click Generate. UUIDs are created instantly in your browser using cryptographically secure randomness. Copy individual UUIDs or all at once.

What is the difference between UUID v1 and UUID v4?

UUID v1 is time-based and includes the MAC address, making it sortable by creation time but potentially revealing device information. UUID v4 is completely random (122 random bits), more commonly used, and reveals no information about when or where it was created.

Which UUID version should I use for my project?

Use UUID v4 for most cases (random, no information leakage, widely supported). Use UUID v7 for database primary keys (sortable, better index performance). Use UUID v5 when you need deterministic IDs from names. Avoid v1 unless you need MAC-based uniqueness.

What is UUID v7 and why is it recommended for databases?

UUID v7 is a new standard (RFC 9562) that combines a Unix timestamp (milliseconds) with random data. It's sortable by creation time, making it ideal for database primary keys. Unlike random v4 UUIDs, v7 UUIDs don't cause index fragmentation and improve query performance.

What is UUID v5 and how does it work?

UUID v5 generates deterministic UUIDs from a namespace and name using SHA-1 hashing. The same namespace + name always produces the same UUID. Useful for creating consistent identifiers from URLs, DNS names, or other strings.

Are UUIDs truly unique and collision-free?

Practically yes. UUID v4 has 122 random bits, giving 5.3×10^36 possible values. The probability of collision is about 1 in 2^122. You would need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one collision.

Can I use UUIDs as database primary keys?

Yes, but choose the right version. UUID v7 is best for primary keys due to its sortable nature and better index performance. Random v4 UUIDs can cause index fragmentation in B-tree indexes. Consider using BINARY(16) storage instead of VARCHAR(36) for efficiency.

What is a namespace UUID and how do I use it?

Namespace UUIDs are well-known UUIDs used with v5 generation to create deterministic IDs. Standard namespaces: DNS (6ba7b810-...), URL (6ba7b811-...), OID (6ba7b812-...), X500 (6ba7b814-...). Combine namespace + your string to generate consistent UUIDs.

How do I validate if a string is a valid UUID?

A valid UUID has the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where M is the version (1-7) and N indicates the variant (8, 9, a, or b for RFC 4122). Use regex: /^[0-9a-f]{8}-[0-9a-f]{4}-[1-7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i

What is the difference between UUID and GUID?

UUID and GUID are essentially the same thing - 128-bit unique identifiers. GUID (Globally Unique Identifier) is Microsoft's term, while UUID (Universally Unique Identifier) is the standard term used in RFC 4122 and RFC 9562. The format and generation methods are identical.

Can I generate UUIDs in bulk for testing?

Yes! Set the quantity to generate multiple UUIDs at once. Perfect for creating test data, seeding databases, generating sample identifiers, or any scenario requiring many unique IDs. All UUIDs are generated instantly in your browser.

Is my UUID data secure and private?

Yes! All UUID generation happens 100% in your browser using JavaScript and the Web Crypto API. Your UUIDs are NEVER sent to any server, stored, or logged. The tool works completely offline for maximum privacy and security.

How do I convert UUID to different formats?

UUIDs can be represented as: standard format (with hyphens), compact format (without hyphens, 32 chars), binary (16 bytes), base64 (22 chars), or integer. The generator provides standard format; remove hyphens for compact format.

What is UUID nil and UUID max?

UUID nil (00000000-0000-0000-0000-000000000000) represents "no UUID" or null. UUID max (ffffffff-ffff-ffff-ffff-ffffffffffff) is the maximum possible value. Both are special values used in specific contexts like database defaults or range queries.

What is a UUID and what does it stand for?

UUID stands for Universally Unique Identifier. It's a 128-bit identifier that is unique across space and time, formatted as xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (36 characters with hyphens). Also known as GUID (Globally Unique Identifier) in Microsoft systems.

How do I generate a UUID online?

Select your desired UUID version (v1, v4, v5, or v7), set the quantity for bulk generation, and click Generate. UUIDs are created instantly in your browser using cryptographically secure randomness. Copy individual UUIDs or all at once.

What is the difference between UUID v1 and UUID v4?

UUID v1 is time-based and includes the MAC address, making it sortable by creation time but potentially revealing device information. UUID v4 is completely random (122 random bits), more commonly used, and reveals no information about when or where it was created.

Which UUID version should I use for my project?

Use UUID v4 for most cases (random, no information leakage, widely supported). Use UUID v7 for database primary keys (sortable, better index performance). Use UUID v5 when you need deterministic IDs from names. Avoid v1 unless you need MAC-based uniqueness.

What is UUID v7 and why is it recommended for databases?

UUID v7 is a new standard (RFC 9562) that combines a Unix timestamp (milliseconds) with random data. It's sortable by creation time, making it ideal for database primary keys. Unlike random v4 UUIDs, v7 UUIDs don't cause index fragmentation and improve query performance.

What is UUID v5 and how does it work?

UUID v5 generates deterministic UUIDs from a namespace and name using SHA-1 hashing. The same namespace + name always produces the same UUID. Useful for creating consistent identifiers from URLs, DNS names, or other strings.

Are UUIDs truly unique and collision-free?

Practically yes. UUID v4 has 122 random bits, giving 5.3×10^36 possible values. The probability of collision is about 1 in 2^122. You would need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one collision.

Can I use UUIDs as database primary keys?

Yes, but choose the right version. UUID v7 is best for primary keys due to its sortable nature and better index performance. Random v4 UUIDs can cause index fragmentation in B-tree indexes. Consider using BINARY(16) storage instead of VARCHAR(36) for efficiency.

What is a namespace UUID and how do I use it?

Namespace UUIDs are well-known UUIDs used with v5 generation to create deterministic IDs. Standard namespaces: DNS (6ba7b810-...), URL (6ba7b811-...), OID (6ba7b812-...), X500 (6ba7b814-...). Combine namespace + your string to generate consistent UUIDs.

How do I validate if a string is a valid UUID?

A valid UUID has the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where M is the version (1-7) and N indicates the variant (8, 9, a, or b for RFC 4122). Use regex: /^[0-9a-f]{8}-[0-9a-f]{4}-[1-7][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i

What is the difference between UUID and GUID?

UUID and GUID are essentially the same thing - 128-bit unique identifiers. GUID (Globally Unique Identifier) is Microsoft's term, while UUID (Universally Unique Identifier) is the standard term used in RFC 4122 and RFC 9562. The format and generation methods are identical.

Can I generate UUIDs in bulk for testing?

Yes! Set the quantity to generate multiple UUIDs at once. Perfect for creating test data, seeding databases, generating sample identifiers, or any scenario requiring many unique IDs. All UUIDs are generated instantly in your browser.

Is my UUID data secure and private?

Yes! All UUID generation happens 100% in your browser using JavaScript and the Web Crypto API. Your UUIDs are NEVER sent to any server, stored, or logged. The tool works completely offline for maximum privacy and security.

How do I convert UUID to different formats?

UUIDs can be represented as: standard format (with hyphens), compact format (without hyphens, 32 chars), binary (16 bytes), base64 (22 chars), or integer. The generator provides standard format; remove hyphens for compact format.

What is UUID nil and UUID max?

UUID nil (00000000-0000-0000-0000-000000000000) represents "no UUID" or null. UUID max (ffffffff-ffff-ffff-ffff-ffffffffffff) is the maximum possible value. Both are special values used in specific contexts like database defaults or range queries.

UUID Generator

simple

Generate UUIDs in v1, v4, v5, and v7 formats. Create universally unique identifiers for databases, APIs, and distributed systems.

Generatorsuuidguidgeneratorunique id

100% Private - Runs Locally

How to Use

1Select UUID version
2Generate single or bulk
3Copy UUIDs
4Use v7 for databases

Examples

UUID v4 (Random)

Input

Generate UUID v4

Output

550e8400-e29b-41d4-a716-446655440000

UUID v1 (Time-based)

Input

Generate UUID v1

Output

6ba7b810-9dad-11d1-80b4-00c04fd430c8

UUID v7 (Sortable)

Input

Generate UUID v7

Output

018e4f8c-5b3a-7000-8000-000000000000

Frequently Asked Questions

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