UUID v3 Generator
Create a name-based UUID v3 by hashing a namespace and a name with MD5. Pick the DNS, URL, OID or X.500 namespace or paste your own; same input, same UUID. The result updates as you type, which makes it easy to check UUID v3 values produced by other libraries.
What is UUID v3?
UUID version 3 is deterministic: instead of using random numbers or the clock, it is calculated from the MD5 hash of a namespace UUID followed by a name (encoded as UTF-8). Anyone who uses the same namespace and name gets exactly the same UUID, so it can be recomputed at any time without storing a mapping. Version 3 is the older of the two name-based versions. RFC 9562 recommends UUID v5 (SHA-1) for new work, so v3 is mainly used to match identifiers in an existing system.
How to use
- Type the text to convert in Name, for example a domain name or a URL.
- Choose a standard namespace from Namespace (DNS, URL, OID or X.500 DN), or type any UUID into Namespace UUID. The selector shows Custom when the namespace is not one of the standard ones.
- The UUID v3 appears below straight away. Copy it or download it as
uuid3.txtwith the buttons in the corner.
The button at the end of Namespace UUID fills in a random UUID v4, which you can use as your own application namespace.
Features
- Live result: no button to press
- The four predefined namespaces from the RFC, plus any custom namespace UUID
- Spaces before or after the namespace UUID are ignored; an invalid namespace shows an error
- One-click random namespace
- Name, namespace and result are kept in this browser
Predefined namespaces
| Namespace | UUID | Use the name as |
|---|---|---|
| DNS | 6ba7b810-9dad-11d1-80b4-00c04fd430c8 | A domain name, e.g. www.example.com |
| URL | 6ba7b811-9dad-11d1-80b4-00c04fd430c8 | A full URL |
| OID | 6ba7b812-9dad-11d1-80b4-00c04fd430c8 | An ISO object identifier |
| X.500 DN | 6ba7b814-9dad-11d1-80b4-00c04fd430c8 | An X.500 distinguished name |
Examples
| Namespace | Name | UUID v3 |
|---|---|---|
| DNS | www.example.com | 5df41881-3aed-3515-88a7-2f4a814cf09e |
| DNS | python.org | 6fa459ea-ee8a-3ca4-894e-db77e160355e |
| URL | https://example.com/ | b9dcdff8-af4a-365d-8043-0f8361942709 |
The python.org value matches uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org') in Python. Note the 3 at the start of the third block: it is the version number.
FAQ
What is the difference between UUID v3 and UUID v5?
Only the hash function. v3 uses MD5 and v5 uses SHA-1 (truncated to fit). The same namespace and name give different UUIDs in v3 and v5, so use the version your other systems use.
Why does my result differ from another tool?
Check that both use the same namespace and exactly the same name. Names are case-sensitive and are not trimmed, so Example.com, example.com and example.com (with a trailing space) all give different UUIDs. A URL with and without a trailing slash also differs.
Is MD5 safe enough?
UUID v3 is meant for identification, not security. Anyone who knows or guesses the name can compute the same UUID, so do not use it as a secret or an access token.
Is my input sent to a server?
No. The hash is calculated in your browser.