UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a1b481-50fe-77f8-8368-8c6432df66a3
01a1b481-50fe-7986-8193-7476324cadbe
01a1b481-50fe-7ac9-9d0e-e603fa6f2f7e
01a1b481-50fe-7be8-835d-41db1fa73e40
01a1b481-50fe-7cfe-ba63-605f36adbaa5
01a1b481-50fe-7e19-8e4d-1246dc5b2945
01a1b481-50fe-7f30-ad78-091b3d594bc6
01a1b481-50ff-7046-9db1-a7cb2be0a220
01a1b481-50ff-715d-9f7d-4eceaf19a829
01a1b481-50ff-7277-bb10-df62c68c9acf
01a1b481-50ff-738e-98bb-48ed87cae1e3
01a1b481-50ff-74a4-98cf-3d9174f9d898
01a1b481-50ff-75bb-920c-742ac51a8c09
01a1b481-50ff-76d1-9891-5fddfccfc751
01a1b481-50ff-77e4-913f-ad6c73b3f773

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)

1f1da6d0-eed4-607e-b3c6-4cf95d479851
1f1da6d0-eed4-622c-b3c6-4cf95d479851
1f1da6d0-eed4-6312-b3c6-4cf95d479851
1f1da6d0-eed4-63e4-b3c6-4cf95d479851
1f1da6d0-eed4-64ac-b3c6-4cf95d479851
1f1da6d0-eed4-6574-b3c6-4cf95d479851
1f1da6d0-eed4-6632-b3c6-4cf95d479851
1f1da6d0-eed4-66fa-b3c6-4cf95d479851
1f1da6d0-eed4-67b8-b3c6-4cf95d479851
1f1da6d0-eed4-6880-b3c6-4cf95d479851
1f1da6d0-eed4-69de-b3c6-4cf95d479851
1f1da6d0-eed4-6ab0-b3c6-4cf95d479851
1f1da6d0-eed4-6b6e-b3c6-4cf95d479851
1f1da6d0-eed4-6c36-b3c6-4cf95d479851
1f1da6d0-eed4-6cf4-b3c6-4cf95d479851

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)

0eed4dd0-da6d-11f1-b3c6-4cf95d479851
0eed4e34-da6d-11f1-b3c6-4cf95d479851
0eed4e98-da6d-11f1-b3c6-4cf95d479851
0eed4ef2-da6d-11f1-b3c6-4cf95d479851
0eed4f56-da6d-11f1-b3c6-4cf95d479851
0eed4fba-da6d-11f1-b3c6-4cf95d479851
0eed501e-da6d-11f1-b3c6-4cf95d479851
0eed5082-da6d-11f1-b3c6-4cf95d479851
0eed50e6-da6d-11f1-b3c6-4cf95d479851
0eed514a-da6d-11f1-b3c6-4cf95d479851
0eed51ae-da6d-11f1-b3c6-4cf95d479851
0eed5208-da6d-11f1-b3c6-4cf95d479851
0eed5280-da6d-11f1-b3c6-4cf95d479851
0eed52e4-da6d-11f1-b3c6-4cf95d479851
0eed5348-da6d-11f1-b3c6-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

42893124-5001-8713-87ea-5ce32bd83b97
50cd3224-5001-8713-87ea-5ce32bd83b97
70cc3324-5001-8713-87ea-5ce32bd83b97
d35d3424-5001-8713-87ea-5ce32bd83b97
46d53524-5001-8713-87ea-5ce32bd83b97
f41e3624-5001-8713-87ea-5ce32bd83b97
55363724-5001-8713-87ea-5ce32bd83b97
61203824-5001-8713-87ea-5ce32bd83b97
18303924-5001-8713-87ea-5ce32bd83b97
2f513a24-5001-8713-87ea-5ce32bd83b97
9a9e3b24-5001-8713-87ea-5ce32bd83b97
77b33c24-5001-8713-87ea-5ce32bd83b97
306a3e24-5001-8713-87ea-5ce32bd83b97
5ad23f24-5001-8713-87ea-5ce32bd83b97
5eb24024-5001-8713-87ea-5ce32bd83b97

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)

63babac4-8969-4c27-8a00-d552013d663e
5db2cfee-32a3-400e-b2fa-3a16ee2699b4
37adb38f-f9bd-44fb-bc94-6e3bbaf08743
49febb68-f1c9-4726-8a7a-f937b987cbcf
17bec425-5de7-4eff-9ec9-21d817c03630
45c89514-49ea-4af7-9d60-36c6a2343356
968298de-cd26-42fc-b8b0-f52efd272124
2c65dae1-f284-401d-9acb-3acea2f19eed
5d899ab2-b466-403c-95a0-ea731726f375
3dd6e079-5390-4171-a228-c313ff0ae310
987781e5-e601-492c-87a2-8c8641e6aac5
63da19b3-ce1d-4305-b8c0-e6f74883a836
92edbb20-f60f-49c3-b714-350fe57eadec
f43487b6-4e16-43f5-81b1-c6511bae9dc1
e040a16f-152b-4e79-aa00-08d73cff53a6

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: