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)

01952e9b-0866-7b30-8593-e6694baeefcd
01952e9b-0866-7cd1-9b86-3ff7239e1a93
01952e9b-0866-7e19-9562-33fe60985b99
01952e9b-0866-7f40-80ec-3bbc2eac9de0
01952e9b-0867-7063-aec3-eefa6d2cf94d
01952e9b-0867-7182-b32e-3bec3fa8eb6e
01952e9b-0867-72a0-b0f1-c07457bd4d8c
01952e9b-0867-73c3-8f28-d03ea9dc4565
01952e9b-0867-74e6-aa25-61a453c834ad
01952e9b-0867-7600-8bcd-01053765daef
01952e9b-0867-771f-a2f8-b20f03c0120f
01952e9b-0867-783e-8610-d7c47487cdc7
01952e9b-0867-795d-b894-1d699d4d4d5f
01952e9b-0867-7a7b-8c91-c1c75f8038a4
01952e9b-0867-7b9a-b914-9ff50373be3e

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)

1eff13e9-b799-685e-8dfa-4cf95d479851
1eff13e9-b799-6a20-8dfa-4cf95d479851
1eff13e9-b799-6b06-8dfa-4cf95d479851
1eff13e9-b799-6bd8-8dfa-4cf95d479851
1eff13e9-b799-6c96-8dfa-4cf95d479851
1eff13e9-b799-6d5e-8dfa-4cf95d479851
1eff13e9-b799-6e12-8dfa-4cf95d479851
1eff13e9-b799-6ed0-8dfa-4cf95d479851
1eff13e9-b79a-602e-8dfa-4cf95d479851
1eff13e9-b79a-6128-8dfa-4cf95d479851
1eff13e9-b79a-62c2-8dfa-4cf95d479851
1eff13e9-b79a-6452-8dfa-4cf95d479851
1eff13e9-b79a-6592-8dfa-4cf95d479851
1eff13e9-b79a-665a-8dfa-4cf95d479851
1eff13e9-b79a-6718-8dfa-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)

ddba1ff2-4118-45b6-9c34-99ba11957c77
bf17ca1e-c264-4699-a451-06ba7db60653
7854d910-414b-43d8-beb0-008940688480
47d6778b-72a9-4ec6-85ab-7845c21a6e8d
03f957dd-626e-4587-84ca-96b68381eb64
56aa4218-b576-40f0-8508-732a57045c48
cefc12fe-b325-4894-9d15-63d964aab84f
548d0b36-31e8-43a7-9e85-a603d1fdd4c5
9b030271-d716-4441-9bce-74cafa48c078
192f5f6a-7de2-4706-8dbf-d7c2ade0fe62
f5657422-ad0f-413f-8e66-5bcc9b18633f
73257410-876f-4c1f-aac5-1db68e57d667
7d23bfe5-4d4b-4a80-ba14-d7bbfe156e30
b9c6bbc7-784a-4885-a4ff-9ac8bc769f5d
dddb8220-6fe9-4e33-bdba-4390370be3f8

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)

9b79ac54-f13e-11ef-8dfa-4cf95d479851
9b79acc2-f13e-11ef-8dfa-4cf95d479851
9b79ad26-f13e-11ef-8dfa-4cf95d479851
9b79ad8a-f13e-11ef-8dfa-4cf95d479851
9b79adee-f13e-11ef-8dfa-4cf95d479851
9b79ae52-f13e-11ef-8dfa-4cf95d479851
9b79aeac-f13e-11ef-8dfa-4cf95d479851
9b79af10-f13e-11ef-8dfa-4cf95d479851
9b79af74-f13e-11ef-8dfa-4cf95d479851
9b79afce-f13e-11ef-8dfa-4cf95d479851
9b79b032-f13e-11ef-8dfa-4cf95d479851
9b79b096-f13e-11ef-8dfa-4cf95d479851
9b79b0f0-f13e-11ef-8dfa-4cf95d479851
9b79b154-f13e-11ef-8dfa-4cf95d479851
9b79b1b8-f13e-11ef-8dfa-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)

58b40c07-03fe-8035-87e9-5ce32bd83b96
56f90d07-03fe-8035-87e9-5ce32bd83b96
d1c60e07-03fe-8035-87e9-5ce32bd83b96
adbe0f07-03fe-8035-87e9-5ce32bd83b96
fbc21007-03fe-8035-87e9-5ce32bd83b96
bf391107-03fe-8035-87e9-5ce32bd83b96
33aa1307-03fe-8035-87e9-5ce32bd83b96
85551407-03fe-8035-87e9-5ce32bd83b96
c1741507-03fe-8035-87e9-5ce32bd83b96
dd961607-03fe-8035-87e9-5ce32bd83b96
a78a1707-03fe-8035-87e9-5ce32bd83b96
2dc21807-03fe-8035-87e9-5ce32bd83b96
9d841907-03fe-8035-87e9-5ce32bd83b96
b53e1a07-03fe-8035-87e9-5ce32bd83b96
719b1b07-03fe-8035-87e9-5ce32bd83b96

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: