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UUID Generator & Decoder

Generate v4 and v7 UUIDs, or paste any UUID to read its version, variant, and embedded timestamp — all in your browser.

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Inspect / decode
That is not a valid UUID. Enter 32 hexadecimal digits in the 8-4-4-4-12 form (hyphens optional).
A UUID is 128 bits, written as 32 hex digits in the 8-4-4-4-12 form. The version is the 13th hex digit and the variant is the 17th. Versions 1 and 7 embed a timestamp this tool extracts as a UTC date; version 4 is random and carries no time or identity data. Note: version 1 historically embedded the generating machine MAC address as its node field, though the RFC also allows a random node. Everything runs in your browser — nothing you generate or paste is sent to a server.

Frequently Asked Questions

What is a UUID?

A UUID is a Universally Unique Identifier, a 128-bit value used to label data without a central authority. It is written as 32 hexadecimal digits in an 8-4-4-4-12 pattern separated by hyphens, for a total of 36 characters. UUIDs are defined by RFC 4122 and updated by RFC 9562.

Is a v4 UUID truly random and unique?

A version 4 UUID uses 122 random or pseudo-random bits, with the remaining 6 bits fixed for the version and variant. Because the random space is so large, a collision between two correctly generated v4 UUIDs is astronomically unlikely rather than mathematically impossible. This tool uses the browser cryptographic random source for v4 generation.

What is the difference between UUID v4 and v7?

Version 4 is fully random and has no time component, so values do not sort in creation order. Version 7 places a 48-bit Unix millisecond timestamp in the first 48 bits and fills the rest with random data, so v7 values are time-ordered. Time ordering makes v7 friendlier for database index locality than v4.

Can a UUID be decoded to reveal anything?

A UUID always encodes its version and variant, which this tool reads from the version and variant positions. Time-based versions reveal more: version 1 and version 7 embed a timestamp that can be extracted as a date. Version 4 is random and carries no embedded time or identity data.

Is this generator safe and does it send my UUID anywhere?

This tool runs entirely in your browser and does not transmit anything you generate or paste to any server. Generation and decoding happen locally using built-in browser functions. Nothing you enter leaves your device.

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