UUID Generator
Generate version 4, version 7 and version 5 UUIDs under RFC 9562, in bulk, in any common format. Validate any UUID to see its version and embedded time, and export your list as TXT, JSON, CSV or SQL, all directly in your browser.
100% client-side · Web Crypto API · Nothing is stored or sent
UUIDs are identifiers, not secrets. Do not use them as passwords or API keys.
How UUIDs Work
A UUID is 128 bits. Six of those bits say which version and variant it is, and the rest depend on the version. In a version 4 UUID the remaining 122 bits are random. In a version 7 UUID the first 48 bits are the Unix time in milliseconds, followed by a 12-bit counter and 62 random bits, so sorting the UUIDs sorts them by creation time. In a version 5 UUID the bits come from the SHA-1 hash of a namespace and a name.
The validator reads those bits back: it tells you the version, the variant, and for versions 1, 6 and 7 the date and time stored inside, so you can check any UUID you meet, including ones in braces, in upper case or without hyphens.
RFC 9562 UUIDs
Version 4, version 7 and version 5, following the 2024 standard that replaced RFC 4122
Ordered Version 7
A built-in counter keeps UUIDs strictly increasing, even when thousands are made in one millisecond
Reads Any Version
The validator accepts v1 to v8, nil and max, in every common format, and shows the embedded time
Name-Based UUIDs
Version 5 from a namespace and a list of names, repeatable and checked against reference implementations
Exports
TXT, JSON, CSV and multi-row SQL, with the SQL always in the canonical form
Nothing Stored
Generated in your browser with no network requests, no history and no external scripts
Explore more free tools in our security tools collection, including our secure token generator and our strong random password generator.
Frequently Asked Questions
1. What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier written as 32 hexadecimal digits in the pattern 8-4-4-4-12, for example 123e4567-e89b-42d3-a456-426614174000. It lets separate systems create identifiers without asking each other, with a negligible chance of two being the same. The standard is RFC 9562, published in May 2024, which replaced RFC 4122.
2. Which UUID version should I use?
Version 4 is 122 random bits and is the general-purpose choice. Version 7 starts with the creation time and sorts in creation order, which makes it the better choice for database primary keys. Version 5 is made from a namespace and a name with SHA-1, so the same input always gives the same UUID. Version 1 and 6 use a timestamp and a node ID, version 3 is the older MD5 name-based form, and version 8 is for custom layouts. This page generates v4, v7 and v5 and can read all of them.
3. How unique is a UUID?
A version 4 UUID has 122 random bits. You would need to create about 2.71 quintillion of them to have a 50% chance of a single duplicate. Version 7 UUIDs from this page have 62 random bits plus a 12-bit counter within each millisecond, so a collision needs two UUIDs made in the same millisecond with matching random bits, which is still extremely unlikely.
4. Why is version 7 better for database keys?
Random version 4 keys land in random places in a database index, which causes page splits and slows inserts on large tables. Version 7 keys increase over time, so new rows are added at the end of the index. The cost is that a version 7 UUID reveals the time it was created, down to the millisecond, so do not use it where that is sensitive.
5. How does this page generate UUIDs?
Version 4 uses the browser’s crypto.randomUUID() when it exists and crypto.getRandomValues otherwise. Version 7 follows RFC 9562 with a 48-bit millisecond timestamp, a 12-bit counter that keeps UUIDs strictly increasing even when many are made in one millisecond, and 62 random bits. Version 5 uses SHA-1 from the Web Crypto API with the namespace you choose. Counts are limited to 10,000 per run.
6. Can I use a UUID as a secret or a password?
No. A UUID is an identifier. A version 4 UUID is hard to guess, but it is not designed as a secret, it often appears in URLs and logs, and version 7 and 5 UUIDs are partly or fully predictable. For API keys, session tokens and similar secrets use our secure token generator.
7. Which formats can the validator read?
Canonical (lowercase with hyphens), upper case, no hyphens, in braces {...} and with the urn:uuid: prefix. It reports the version, the variant, the canonical form and, for versions 1, 6 and 7, the time stored inside the UUID. The SQL export always uses the canonical form, which is what database UUID columns expect, while the other exports follow your format choices.
8. Is my data stored or sent anywhere?
No. Everything is generated in your browser, the page’s content security policy blocks outgoing network requests, and nothing is saved except your language choice. Earlier versions of this page loaded a script from an outside server, only accepted version 4 UUIDs (so it rejected valid UUIDs of other versions and even its own hyphen-less output), and produced a fresh random value one hex digit at a time.