UUID/GUID numbers generator
Calculator generates UUID/GUID numbers. The versions v1, v3, v4 and v5 are supported.

Beta version#

This online calculator is currently under heavy development. It may or it may NOT work correctly.
You CAN try to use it. You CAN even get the proper results.
However, please VERIFY all results on your own, as the level of completion of this item is NOT CONFIRMED.
Feel free to send any ideas and comments !

Version and parameters of your UUID/GUID#

UUID version
UUID version, which we want to use
Name and namespace (v3 and v5 only)
Name to encode
Namespace UUID
Generate more UUID-s

Results: UUID/GUID numbers generated for you#


Some facts#

  • The UUID is a Universally Unique IDentifier. We can use it to identify objects in the global space.
  • UUID number consists of 128 bits which corresponds to 16 bytes.
  • UUID in text format is usually written as 32 characters separated by dashes which corresponds to the values ​​of subsequent bytes in hexadecimal system starting with the most significant (the so-called big endian order) e.g.

  • The UUID format is standarized in RFC 4122 document.
  • The meaning of individual bytes is different depending on the version and variant (sometimes called a revision) used. RFC 4122 defines 5 versions:
    • version 1 - based on a 60-bit time stamp and 48-bit MAC address,
    • version 2 - modification of version 1 intended for DCE security standards,
    • version 3 - based on the MD5 hash of a known name, e.g. domain or URL, but the meaning of the name is not imposed by the specification,
    • version 4 - based entirely on random numbers or pseudorandom,
    • version 5 - modification of version 3 using the hash function SHA-1.
  • A sample UUID in version 1 contains:
    f68b5140time_low4 bytesed89time_mid2 bytes11ebtime_high_and_version2 bytesa44cclock_seq_and_res2 bytes69d32820f390node6 bytes \underbrace{\overbrace{f68b5140}^{\text{time\_low}}}_{\text{4 bytes}} - \underbrace{\overbrace{ed89}^{\text{time\_mid}}}_{\text{2 bytes}} - \underbrace{\overbrace{11eb}^{\text{time\_high\_and\_version}}}_{\text{2 bytes}} - \underbrace{\overbrace{a44c}^{\text{clock\_seq\_and\_res}}}_{\text{2 bytes}} - \underbrace{\overbrace{69d32820f390}^{\text{node}}}_{\text{6 bytes}}
    • time_low - the least significant 32 bits of the 60-bit timestamp (0xf68b5140),
    • time_mid - next 16 bits of the 60-bit timestamp (0xed89) ,
    • time_high_and_version - the most significant 12 bits of the 60-bit timestamp and 4-bit version number (0x11eb),
    • clock_seq_and_res - 14-bit clock sequence and variant number (0xa44),
    • node - 48-bit (6 byte) MAC address (0x69d32820f390 or 69:d3:28:20:f3:90).
  • The UUID timestamp encoded in versions 1 and 2 is 60 bits. It corresponds to the number of 100 nanosecond intervals since October 15, 1582 which corresponds to the beginning of the Gregorian calendar.
  • Versions 1 and 2 contain the encoded 48-bit MAC address of the host, where the UUID was generated. When the MAC address is unavailable, it is allowed to use a random number - in this case the generated number should have the multicast bit set.
  • The uniqueness of UUID numbers is based on low probability of collision. Versions 1 and 2 also use the MAC address of the host, which is assumed to uniquely identify the network device in the global scale.

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