UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate random and/or time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate random (version 4) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate other UUID types
  • NCS (variant 0) UUID
  • Generate DCE Security (version 2) UUID
  • Generate name-based (version 3 / 5 / New: 8) UUID
  • New: Generate Custom (version 8) UUID
• Interpret a UUID
• Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)
  • Generate an AAI

Generate random and/or time-based UUIDs

New: Generate Unix Epoch time-based (version 7) UUID ⭐

A UUIDv7 measures time in the Unix Epoch with an accuracy between 1ms and 245ns, depending on how many bits are spent for the timestamp (48-60 bits). The rest of the UUID (62-74 bits) is filled with random data. The timestamp is at the front of the UUID, therefore the UUIDs are monotonically increasing, which is good for using them in database indexes. Since this UUID version does not contain a MAC address, it is also recommended due to the improved privacy.

Show format

Variant 1, Version 7 UUID:
- 48 bit Unix Time in milliseconds
-  4 bit Version (fix 0x7)
- 12 bit Data
-  2 bit Variant (fix 0b10)
- 62 bit Data

Structure of data (74 bits):
- OPTIONAL : Sub-millisecond timestamp fraction (0-12 bits)
- OPTIONAL : Carefully seeded counter
- Random generated bits for any remaining space

Time resolution for various sub-millisecond bits:
0 bits fraction = 1 ms
1 bits fraction = 500 µs
2 bits fraction = 250 µs
3 bits fraction = 125 µs
4 bits fraction = 62.5 µs
5 bits fraction = 31.25 µs
6 bits fraction = 15.625 µs
7 bits fraction = 7.8125 µs
8 bits fraction = 3.90625 µs
9 bits fraction = 1.953125 µs
10 bits fraction = 976.5625 ns
11 bits fraction = 488.28125 ns
12 bits fraction = 244.140625 ns

This implementation outputs:
- 12 bits sub-millisecond timestamp (~245ns resolution)
- no counter
- 62 bits random data

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

0192d77c-e064-76b1-97f2-99b9b618e9ad
0192d77c-e064-7836-8718-fda9ab2f779a
0192d77c-e064-797d-be35-c22a3e0dc1b7
0192d77c-e064-7aa0-8223-2f52d1ceeef7
0192d77c-e064-7bbf-9cf2-1417bec1f8f7
0192d77c-e064-7cda-b31d-0bb1ee276e29
0192d77c-e064-7df4-8e05-bb137cd611ef
0192d77c-e064-7f13-9f03-9ca98963528a
0192d77c-e065-702e-8cdc-f99a13de8024
0192d77c-e065-714c-84e6-0864e9b8e2d3
0192d77c-e065-7267-bec0-2095082a9e86
0192d77c-e065-7382-86c0-83425a8de165
0192d77c-e065-749c-bd6f-0a09914806b9
0192d77c-e065-75b3-89a6-fd6d780e19a4
0192d77c-e065-76d1-bf85-5d3cf9b4c8af

New: Generate reordered Gregorian time-based (version 6) UUID ⏰

Like UUIDv1, this kind of UUID is made of the MAC address of the generating computer, the time, and a clock sequence. However, the components in UUIDv6 are reordered (time is at the beginning), so that UUIDs are monotonically increasing, which is good for using them in database indexes.

Show format

Variant 1, Version 6 UUID:
- 48 bit High Time
-  4 bit Version (fix 0x6)
- 12 bit Low Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

1ef95d39-17eb-6e72-868d-4cf95d479851
1ef95d39-17ec-6016-868d-4cf95d479851
1ef95d39-17ec-60fc-868d-4cf95d479851
1ef95d39-17ec-61c4-868d-4cf95d479851
1ef95d39-17ec-6282-868d-4cf95d479851
1ef95d39-17ec-634a-868d-4cf95d479851
1ef95d39-17ec-6408-868d-4cf95d479851
1ef95d39-17ec-64c6-868d-4cf95d479851
1ef95d39-17ec-6584-868d-4cf95d479851
1ef95d39-17ec-664c-868d-4cf95d479851
1ef95d39-17ec-6782-868d-4cf95d479851
1ef95d39-17ec-684a-868d-4cf95d479851
1ef95d39-17ec-6908-868d-4cf95d479851
1ef95d39-17ec-69c6-868d-4cf95d479851
1ef95d39-17ec-6a7a-868d-4cf95d479851

Generate random (version 4) UUID 🎲

A UUIDv4 is made of 122 random bits. No other information is encoded in this kind of UUID.

Show format

Variant 1, Version 4 UUID:
- 48 bit Random High
-  4 bit Version (fix 0x4)
- 12 bit Random Mid
-  2 bit Variant (fix 0b10)
- 62 bit Random Low

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

751c56f3-e78e-4872-a8c8-d74fb4e12499
c3293de3-f1a5-4568-b1ae-20eb10cc0e9a
779bde65-5b54-4c45-aada-177720ba4c0a
f9af4aa4-ce72-474f-b6cf-aa4f5d0dab40
f3a60ead-458b-45fc-b671-c66757ccfd51
5f0080c7-3025-43ac-b4ed-002c56163b69
194cf36d-721c-4930-aaaf-01ba98cd88b1
84e8265b-9e4d-4203-9641-13f91f68bc15
4aefd1a6-9b98-428d-b8a7-3f177b27a85e
e3028ffa-7179-482b-962f-19eb646a0248
ba0cdc9f-4633-4765-b8bb-b94196ff2621
370127f7-9292-4039-ae72-8a15b2433c93
bb36062c-0b25-47f8-99ef-a595f580cd6c
7b4f8791-ecb5-4f90-a1ad-b3985cdf2aaa
6083f608-ca97-4e54-a7fb-15f56d88db01

Generate Gregorian time-based (version 1) UUID ⏰

A UUIDv1 is made of the MAC address of the generating computer, the time, and a clock sequence.

Show format

Variant 1, Version 1 UUID:
- 32 bit Low Time
- 16 bit Mid Time
-  4 bit Version (fix 0x1)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

917ecf8e-95d3-11ef-868d-4cf95d479851
917ecff2-95d3-11ef-868d-4cf95d479851
917ed060-95d3-11ef-868d-4cf95d479851
917ed0c4-95d3-11ef-868d-4cf95d479851
917ed128-95d3-11ef-868d-4cf95d479851
917ed182-95d3-11ef-868d-4cf95d479851
917ed1e6-95d3-11ef-868d-4cf95d479851
917ed24a-95d3-11ef-868d-4cf95d479851
917ed2a4-95d3-11ef-868d-4cf95d479851
917ed308-95d3-11ef-868d-4cf95d479851
917ed362-95d3-11ef-868d-4cf95d479851
917ed3c6-95d3-11ef-868d-4cf95d479851
917ed420-95d3-11ef-868d-4cf95d479851
917ed484-95d3-11ef-868d-4cf95d479851
917ed4e8-95d3-11ef-868d-4cf95d479851

Generate SQL Server sortable time-based (version 8) UUID

The sorting of UUIDs in SQL Server is rather confusing and incompatible with UUIDv6 and UUIDv7.
Therefore this method developed by HickelSOFT generates UUIDs which are sortable by SQL Server.
They have a time resolution of 1 milliseconds combined with 16 bits of random data.
C# implementation | PHP implementation

Show format

Version 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 16 bit Random data
-  8 bit UTC Milliseconds transformed from 1000ms to 0..255, deviation -2ms..2ms (hex encoded)
-  8 bit UTC Seconds (hex encoded)
- 16 bit UTC Minute of the day (1..1440, hex encoded)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b96

Version 1: Resolution of 1 milliseconds, random part of 16 bits, local timezone, 48 zero bits "signature", NOT UUIDv8 conform:
- 16 bit Random data
-  8 bit Generator's local timezone Milliseconds transformed from 1000ms to 0..255, deviation -4ms..0ms (hex encoded)
-  8 bit Generator's local timezone Seconds (BCD encoded)
-  8 bit Generator's local timezone Minute (BCD encoded)
-  8 bit Generator's local timezone Hour (BCD encoded)
-  8 bit Generator's local timezone Day (BCD encoded)
-  8 bit Generator's local timezone Month (BCD encoded)
-  8 bit Generator's local timezone 2-digit year (BCD encoded)
-  8 bit Generator's local timezone 2-digit century (BCD encoded)
- 48 bit Signature 0x000000000000

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

18615726-0218-812f-87e8-5ce32bd83b96
e6e85826-0218-812f-87e8-5ce32bd83b96
23a95926-0218-812f-87e8-5ce32bd83b96
6ee25a26-0218-812f-87e8-5ce32bd83b96
53025b26-0218-812f-87e8-5ce32bd83b96
1a8c5c26-0218-812f-87e8-5ce32bd83b96
6b4f5d26-0218-812f-87e8-5ce32bd83b96
2a6d5e26-0218-812f-87e8-5ce32bd83b96
15865f26-0218-812f-87e8-5ce32bd83b96
d2e76026-0218-812f-87e8-5ce32bd83b96
d1b76226-0218-812f-87e8-5ce32bd83b96
5c8d6326-0218-812f-87e8-5ce32bd83b96
c31d6426-0218-812f-87e8-5ce32bd83b96
a7476526-0218-812f-87e8-5ce32bd83b96
8df06626-0218-812f-87e8-5ce32bd83b96

Generate other UUID types

The following types of UUIDs are less common and/or require special knowledge. Please only use the following generators if you know what you are doing.

NCS (variant 0) UUID

The NCS UUIDs are a legacy format initially designed by Apollo Computer that cannot be generated anymore, because the amount of available timestamp bits was exhausted on 5 September 2015. As an example, here is the last possible NCS UUID (all bits of the timestamp are set to 1) for IP address 127.0.0.1: ffffffff-ffff-0000-027f-000001000000.

Show format

Variant 0 UUID:
- 32 bit High Time
- 16 bit Low Time
- 16 bit Reserved
-  1 bit Variant (fix 0b0)
-  7 bit Family
- 56 bit Node

Generate DCE Security (version 2) UUID

An UUIDv2 contains information about the creator (person, group, or organization), the generating system (MAC address), and time. The creator information replaced parts of the time bits, therefore the time resolution is very low.

Show format

Variant 1, Version 2 UUID:
- 32 bit Local Domain Number
- 16 bit Mid Time
-  4 bit Version (fix 0x2)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence
-  8 bit Local Domain
- 48 bit MAC Address

Generate name-based (version 3 / 5 / New: 8) UUID

An UUIDv3 is made out of a MD5 hash and an UUIDv5 is made out of a SHA1 hash. RFC 9562 also contains an example for a custom UUIDv8 implementation that uses modern hash algorithms.

Show format

Variant 1, Version 3/5/8 UUID:
- 48 bit Hash High
-  4 bit Version (fix 0x3, 0x5, or 0x8)
- 12 bit Hash Mid
-  2 bit Variant (fix 0b10)
- 62 bit Hash Low


As shown in RFC 9562 Appendix B.2:
UUIDv8(HashAlgo, NameSpaceUuid, Data) := ConvertRawBytesToUuid_v8(HashAlgo( Binary[NameSpaceUuid] || Data )).

New: Generate Custom (version 8) UUID

UUIDv8 is made of 122 bits application-specific / custom data. The other 6 bits are used to specify the variant and version of the UUID, to make it RFC-compatible.

Show format

Variant 1, Version 8 UUID:
- 48 bit Custom data [Block 1+2]
-  4 bit Version (fix 0x8)
- 12 bit Custom data [Block 3]
-  2 bit Variant (fix 0b10)
- 62 bit Custom data [Block 4+5]

Interpret a UUID

You can enter a UUID in the following notations:

• Classic notation (case insensitive, curly braces optional): 9e83839a-5967-11e4-8c1c-78e3b5fc7f22
• As OID: 2.25.210700883446948645633376489934419689250

The script will output:

• Notation as UUID and OID
• Version, variant, and additional data (date and time, clock sequence, node id, etc.)

Please enter a UUID or UUID OID:

Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)

You can enter a UUID in the following notations:

• AA-BB-CC-DD-EE-FF
• AA:BB:CC:DD:EE:FF
• AABBCC.DDEEFF (case insensitive)
• AA-BB-CC-DD-EE-FF-11-22 (EUI-64)
• AA:BB:CC:DD:EE:FF-11-22 (EUI-64)
• fe80::1322:33ff:fe44:5566 (IPv6 Link Local / EUI-64)

The script will output:

• Information about the I/G and U/L flags.
• Information about the entry in the IEEE registry, if available.
• Information about the registrant, if available.

Please enter a MAC (EUI, ELI, SAI, AAI), or IPv6-Link-Local address:

Generate an AAI

An Administratively Assigned Identifier (AAI) is a MAC address which can be locally defined by applications or an administrator. Unlike the EUI, an AAI is NOT worldwide unique.

The following options are rather unusual, but are implemented for the sake of completeness: