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)

019a785d-f8e5-77cb-8094-22e222432983
019a785d-f8e5-7961-923a-868636b33bd5
019a785d-f8e5-7aa4-b771-a2c8ec8d0edb
019a785d-f8e5-7bc7-b813-fad4e0532713
019a785d-f8e5-7ce2-a2c3-5bd9f93950be
019a785d-f8e5-7dfc-b002-290563337100
019a785d-f8e5-7f1b-8eed-532dfa887327
019a785d-f8e6-7036-be5f-0cbb8f05eece
019a785d-f8e6-7150-818e-48ae05b2524f
019a785d-f8e6-726b-b616-247964336db4
019a785d-f8e6-7386-a8aa-4595febf0000
019a785d-f8e6-74a0-ad9e-4c8a2f2eb467
019a785d-f8e6-75bf-915c-e4da32978e6e
019a785d-f8e6-76d5-9e62-7507e568c1fd
019a785d-f8e6-77f4-94aa-89d20d9bf70a

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)

1f0bfcfe-a4be-6f94-b3a9-4cf95d479851
1f0bfcfe-a4bf-612e-b3a9-4cf95d479851
1f0bfcfe-a4bf-6214-b3a9-4cf95d479851
1f0bfcfe-a4bf-62e6-b3a9-4cf95d479851
1f0bfcfe-a4bf-63b8-b3a9-4cf95d479851
1f0bfcfe-a4bf-648a-b3a9-4cf95d479851
1f0bfcfe-a4bf-6552-b3a9-4cf95d479851
1f0bfcfe-a4bf-661a-b3a9-4cf95d479851
1f0bfcfe-a4bf-66e2-b3a9-4cf95d479851
1f0bfcfe-a4bf-67aa-b3a9-4cf95d479851
1f0bfcfe-a4bf-6908-b3a9-4cf95d479851
1f0bfcfe-a4bf-69da-b3a9-4cf95d479851
1f0bfcfe-a4bf-6a98-b3a9-4cf95d479851
1f0bfcfe-a4bf-6b56-b3a9-4cf95d479851
1f0bfcfe-a4bf-6c1e-b3a9-4cf95d479851

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)

58665cc8-1449-4094-b4ac-2b7ef2003496
61dd349b-0b7e-458a-9722-cdd49f3d1b69
4453de05-6211-4922-9fa2-7c0c997a2b1b
c6cba6fb-6989-4df7-928c-b49a843f22c9
54f25bed-b3d5-49d9-ad3e-869c2846ad0e
a855febb-f944-4ba6-8d26-8df176e5a9f9
fc1c1b4d-f2db-426b-a821-8f5c0da1a286
88da367c-c8bc-4f74-af08-c71c25577005
7ec81759-9b13-4d02-a79f-15f902e55218
332858e6-b47a-44ae-9a8b-5034de5317b5
21d02cb8-afd1-4725-8b74-b6ff02b361f0
c85eaaac-8269-46e0-86da-f7f25e30793d
e6838134-3521-4ff4-9d40-e079c525536f
a3c3a9f8-e260-44ff-8b4f-78ab40e6c9d5
be3b46b4-b6e9-4847-af75-0b17ddb0ec87

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)

ea4c0132-bfcf-11f0-b3a9-4cf95d479851
ea4c01aa-bfcf-11f0-b3a9-4cf95d479851
ea4c0218-bfcf-11f0-b3a9-4cf95d479851
ea4c027c-bfcf-11f0-b3a9-4cf95d479851
ea4c02ea-bfcf-11f0-b3a9-4cf95d479851
ea4c034e-bfcf-11f0-b3a9-4cf95d479851
ea4c03b2-bfcf-11f0-b3a9-4cf95d479851
ea4c0416-bfcf-11f0-b3a9-4cf95d479851
ea4c0470-bfcf-11f0-b3a9-4cf95d479851
ea4c04d4-bfcf-11f0-b3a9-4cf95d479851
ea4c0542-bfcf-11f0-b3a9-4cf95d479851
ea4c05a6-bfcf-11f0-b3a9-4cf95d479851
ea4c0614-bfcf-11f0-b3a9-4cf95d479851
ea4c0678-bfcf-11f0-b3a9-4cf95d479851
ea4c06dc-bfcf-11f0-b3a9-4cf95d479851

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)

8f93d80f-4903-8c13-87e9-5ce32bd83b97
eb25d90f-4903-8c13-87e9-5ce32bd83b97
d362da0f-4903-8c13-87e9-5ce32bd83b97
28c3db0f-4903-8c13-87e9-5ce32bd83b97
18bedc0f-4903-8c13-87e9-5ce32bd83b97
23a0dd0f-4903-8c13-87e9-5ce32bd83b97
9eabde0f-4903-8c13-87e9-5ce32bd83b97
c0a1df0f-4903-8c13-87e9-5ce32bd83b97
7c88e00f-4903-8c13-87e9-5ce32bd83b97
f9a6e20f-4903-8c13-87e9-5ce32bd83b97
e4f2e30f-4903-8c13-87e9-5ce32bd83b97
2d54e40f-4903-8c13-87e9-5ce32bd83b97
7c8ee50f-4903-8c13-87e9-5ce32bd83b97
eed2e60f-4903-8c13-87e9-5ce32bd83b97
171ce70f-4903-8c13-87e9-5ce32bd83b97

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

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: