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)

019bdb3c-89ce-7d7d-ba51-98c7fa85da6c
019bdb3c-89ce-7f17-917b-7a4681d8c226
019bdb3c-89cf-705b-9537-64837095551e
019bdb3c-89cf-717d-8c1d-a9e747a3374c
019bdb3c-89cf-7298-9c14-e1ea24116720
019bdb3c-89cf-73af-8053-340b26dbe5b1
019bdb3c-89cf-74c9-b099-a07d17eedd6c
019bdb3c-89cf-75e0-81f8-14909197cc07
019bdb3c-89cf-76f6-90c1-32edba0e3edd
019bdb3c-89cf-780d-b19f-d80f28e27e62
019bdb3c-89cf-7927-9cbf-1dd846a961e6
019bdb3c-89cf-7a3e-bda7-6cc2c592c2a2
019bdb3c-89cf-7b59-be4e-ab0559338bf0
019bdb3c-89cf-7c6f-bf2a-889bb6bc3f80
019bdb3c-89cf-7d86-9b2f-65815ccf30d2

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)

1f0f5f60-0488-6aa8-a6a9-4cf95d479851
1f0f5f60-0488-6c4c-a6a9-4cf95d479851
1f0f5f60-0488-6d32-a6a9-4cf95d479851
1f0f5f60-0488-6dfa-a6a9-4cf95d479851
1f0f5f60-0488-6eb8-a6a9-4cf95d479851
1f0f5f60-0488-6f76-a6a9-4cf95d479851
1f0f5f60-0489-603e-a6a9-4cf95d479851
1f0f5f60-0489-60fc-a6a9-4cf95d479851
1f0f5f60-0489-61ba-a6a9-4cf95d479851
1f0f5f60-0489-6278-a6a9-4cf95d479851
1f0f5f60-0489-63ae-a6a9-4cf95d479851
1f0f5f60-0489-6476-a6a9-4cf95d479851
1f0f5f60-0489-652a-a6a9-4cf95d479851
1f0f5f60-0489-65e8-a6a9-4cf95d479851
1f0f5f60-0489-66a6-a6a9-4cf95d479851

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)

fdbcf805-79db-4980-9741-d75ff486180f
f4bc9c19-8745-4f17-9f79-c4aa6f4e4a0c
e00fe57b-7295-44c7-8375-2701b2ad72af
d3d12e04-70e5-402f-b5c4-b04d41b92ed2
c9753888-01a9-427f-99bd-1cc49a832945
8cc4db00-152b-4801-8311-995b058c3698
80575204-a2c1-4b3c-83ae-b69e412d2ed2
d17f4079-544a-45bb-a1c4-9ecb81b72e1f
827e02e5-6389-4dfb-9e81-6034b1171b73
e4aa207b-0b4d-4f14-a229-0c376c24fc45
73b7c5fb-9f0c-430b-9876-d49b216578e9
a3294f59-4439-461a-956a-594d9bcb0549
02c62a53-f385-4250-a19e-54d704beea80
9bc4aa88-37ca-497a-9db0-69af037aec61
59b17f23-f893-4000-9095-282e1ff18606

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)

00489bba-f5f6-11f0-a6a9-4cf95d479851
00489c1e-f5f6-11f0-a6a9-4cf95d479851
00489c82-f5f6-11f0-a6a9-4cf95d479851
00489cdc-f5f6-11f0-a6a9-4cf95d479851
00489d40-f5f6-11f0-a6a9-4cf95d479851
00489d9a-f5f6-11f0-a6a9-4cf95d479851
00489df4-f5f6-11f0-a6a9-4cf95d479851
00489e4e-f5f6-11f0-a6a9-4cf95d479851
00489eb2-f5f6-11f0-a6a9-4cf95d479851
00489f16-f5f6-11f0-a6a9-4cf95d479851
00489f70-f5f6-11f0-a6a9-4cf95d479851
00489fd4-f5f6-11f0-a6a9-4cf95d479851
0048a042-f5f6-11f0-a6a9-4cf95d479851
0048a0b0-f5f6-11f0-a6a9-4cf95d479851
0048a114-f5f6-11f0-a6a9-4cf95d479851

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 3: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 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) LITTLE ENDIAN (CD AB = 0xABCD)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) LITTLE ENDIAN (8C AB = 0xABC)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b97

Version 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 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) BIG ENDIAN (AB CD = 0xABCD) = WRONG!!!
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) BIG ENDIAN (8A BC = 0xABC) = WRONG!!!
-  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 compliant:
- 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)

c83d6638-c502-8401-87ea-5ce32bd83b97
73316738-c502-8401-87ea-5ce32bd83b97
53f86838-c502-8401-87ea-5ce32bd83b97
96146938-c502-8401-87ea-5ce32bd83b97
57ad6a38-c502-8401-87ea-5ce32bd83b97
8eb66b38-c502-8401-87ea-5ce32bd83b97
8ca26c38-c502-8401-87ea-5ce32bd83b97
75026e38-c502-8401-87ea-5ce32bd83b97
827c6f38-c502-8401-87ea-5ce32bd83b97
cbab7038-c502-8401-87ea-5ce32bd83b97
f5377138-c502-8401-87ea-5ce32bd83b97
4a627238-c502-8401-87ea-5ce32bd83b97
7eea7338-c502-8401-87ea-5ce32bd83b97
2e157438-c502-8401-87ea-5ce32bd83b97
9ce77538-c502-8401-87ea-5ce32bd83b97

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

A 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

A UUIDv3 is made out of a MD5 hash and a 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: