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)

01a0c06c-2d89-723a-86d1-28875ec9b8ff
01a0c06c-2d89-7400-9759-054eed81b5de
01a0c06c-2d89-753c-bb77-afcac8bb0e29
01a0c06c-2d89-765b-ab49-c037f6437ae5
01a0c06c-2d89-7775-b27b-c3d025c2ae98
01a0c06c-2d89-7890-b7e3-739c8c5fd6d3
01a0c06c-2d89-79a6-9afa-98c6cbef63d9
01a0c06c-2d89-7ac1-8481-f303ad4ea626
01a0c06c-2d89-7bd8-b56f-70b374b17519
01a0c06c-2d89-7cee-a73a-77f709304e1b
01a0c06c-2d89-7e05-9541-6dc503c06db8
01a0c06c-2d89-7f1b-9e1d-2b5cee7ce425
01a0c06c-2d8a-703a-b10e-77e163b7ca43
01a0c06c-2d8a-7154-97ce-04a40b973ab3
01a0c06c-2d8a-726b-9101-3e51a1886156

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)

1f1b52e9-5342-69c2-bca1-4cf95d479851
1f1b52e9-5342-6b66-bca1-4cf95d479851
1f1b52e9-5342-6c4c-bca1-4cf95d479851
1f1b52e9-5342-6d14-bca1-4cf95d479851
1f1b52e9-5342-6de6-bca1-4cf95d479851
1f1b52e9-5342-6eae-bca1-4cf95d479851
1f1b52e9-5342-6f76-bca1-4cf95d479851
1f1b52e9-5343-603e-bca1-4cf95d479851
1f1b52e9-5343-6106-bca1-4cf95d479851
1f1b52e9-5343-61c4-bca1-4cf95d479851
1f1b52e9-5343-62fa-bca1-4cf95d479851
1f1b52e9-5343-63d6-bca1-4cf95d479851
1f1b52e9-5343-64a8-bca1-4cf95d479851
1f1b52e9-5343-6566-bca1-4cf95d479851
1f1b52e9-5343-6624-bca1-4cf95d479851

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)

9534370a-b52e-11f1-bca1-4cf95d479851
95343778-b52e-11f1-bca1-4cf95d479851
953437dc-b52e-11f1-bca1-4cf95d479851
9534384a-b52e-11f1-bca1-4cf95d479851
953438b8-b52e-11f1-bca1-4cf95d479851
9534391c-b52e-11f1-bca1-4cf95d479851
95343980-b52e-11f1-bca1-4cf95d479851
953439e4-b52e-11f1-bca1-4cf95d479851
95343a3e-b52e-11f1-bca1-4cf95d479851
95343aa2-b52e-11f1-bca1-4cf95d479851
95343b10-b52e-11f1-bca1-4cf95d479851
95343b74-b52e-11f1-bca1-4cf95d479851
95343bd8-b52e-11f1-bca1-4cf95d479851
95343c46-b52e-11f1-bca1-4cf95d479851
95343caa-b52e-11f1-bca1-4cf95d479851

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)

9fad270a-b604-8710-87ea-5ce32bd83b97
2db5280a-b604-8710-87ea-5ce32bd83b97
29722a0a-b604-8710-87ea-5ce32bd83b97
494e2b0a-b604-8710-87ea-5ce32bd83b97
98642c0a-b604-8710-87ea-5ce32bd83b97
d1a32d0a-b604-8710-87ea-5ce32bd83b97
34cc2e0a-b604-8710-87ea-5ce32bd83b97
acd22f0a-b604-8710-87ea-5ce32bd83b97
a832300a-b604-8710-87ea-5ce32bd83b97
fa33310a-b604-8710-87ea-5ce32bd83b97
f925320a-b604-8710-87ea-5ce32bd83b97
2dee330a-b604-8710-87ea-5ce32bd83b97
76e0340a-b604-8710-87ea-5ce32bd83b97
f93e350a-b604-8710-87ea-5ce32bd83b97
bf36360a-b604-8710-87ea-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)

f27dc956-d849-43a5-b026-7177ccbc4e9a
ae9b6f5e-bb77-4835-9100-6ef400341512
f0fbc976-0521-4b7b-8a76-ee6b27ee8209
b828a90e-ec60-4114-aa3a-7610e59bd4d1
760c74dd-6ff7-44bb-a7e7-e070cfaae3c0
5c20b95f-ceeb-4200-b41e-e654661f7d7d
c7ab52bb-55aa-4d1b-afa2-4a370a4d91e5
23fc073b-1130-4e37-944e-04deb7357e6a
3deba7f8-5369-44c7-8885-05661a0f8bc6
f891c05f-4580-4c71-a8bd-9c160686f655
6e8f1fa6-fd2d-46d2-8f4a-07d8e0dfe106
9837f230-6ada-454a-8384-de100436fadd
73e9e282-c1ae-4f42-88d1-e646d4f14512
cddd64f1-e6f6-4e9f-92f7-f00fcd20b264
c7d19faa-b123-4313-bfdb-abd60aab7fcb

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: