UUID Generator

Generate UUIDs (GUIDs) in v4 and v7 formats.

UUID Version

Count (1 - 1000)

UUIDs (Universally Unique Identifiers) are 128-bit labels used to identify records in distributed systems, API resources, databases, event streams, and frontend component keys. Our free UUID Generator produces RFC 9562 compliant Version 4 (random) and Version 7 (time-ordered random) UUIDs in bulk.

Select the version you need: Version 4 (completely random, by far the most common) or Version 7 (time-ordered with millisecond-precision timestamp prefix, ideal for database primary keys as they index naturally in time order). Choose how many UUIDs to generate at once, from 1 to 1,000.

Each generated UUID is in its canonical 8-4-4-4-12 hexadecimal string format with hyphens. Use the Copy button on any individual UUID or the "Copy All" button to copy the entire list to your clipboard. Download as plain text (.txt) is also available for bulk use.

The probability of generating a duplicate UUID is astronomically low: the UUID space has 2^122 possible values for Version 4. Even generating one billion UUIDs per second for 85 years would give about a 50% chance of a single collision, per the Birthday Paradox.

Frequently Asked Questions

What is the difference between UUID v4 and v7?

v4 is 100% randomly generated (122 bits of randomness, 6 bits for version/variant). It is simple and universal. v7 embeds a 48-bit Unix millisecond timestamp in the first 12 hex characters, followed by 74 bits of randomness. v7 is ideal for database primary keys because values sort naturally in insertion order, improving B-tree index locality.

Should I use UUID as a database primary key?

Generally yes, especially for distributed systems. v4 is the standard; v7 is newer (RFC 9562, Feb 2024) and recommended for new systems that benefit from time-ordered insertion. Be aware that default UUIDs are 16 bytes vs. 4/8 bytes for int/bigint auto IDs — there is a storage and index size trade-off.

Are the generated UUIDs stored or logged?

No. UUIDs are generated purely in your browser using the Web Crypto API. They never cross the network and are never seen by our servers. For sensitive applications you can verify this by monitoring your network tab — no network calls are made when you click Generate.

What is the 00000000-0000-0000-0000-000000000000 UUID?

That is the nil UUID (all zeros). It is the canonical representation of "no value" or null UUID. It is commonly used as a placeholder, sentinel value, or default value when a UUID field has not yet been assigned. Our generator never produces it by random chance (or rather, it would happen once in 10^36 generations).

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