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)

019f2029-676d-7c90-8b2e-886916bcaf57
019f2029-676d-7e84-9e5d-8f9b5874728d
019f2029-676d-7fc3-aeab-e7fd6df7be07
019f2029-676e-70e6-9e7d-603166fc3792
019f2029-676e-7205-9e8b-ce865db4b65c
019f2029-676e-731f-9076-357e0452cbb7
019f2029-676e-743e-8fd7-4bf712b6cc88
019f2029-676e-7559-ba8f-4245107dfd02
019f2029-676e-766f-a928-1dfe02ec9421
019f2029-676e-7792-9b97-20817bd8d145
019f2029-676e-78de-b28c-8ca225e9585d
019f2029-676e-79f8-8c66-55e7a779c135
019f2029-676e-7b13-aaab-e1dad56511ee
019f2029-676e-7c29-842b-8af949fe9b77
019f2029-676e-7d44-b474-ecc32b9d9aa0

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)

1f175aa6-4d99-6da2-a048-4cf95d479851
1f175aa6-4d99-6f8c-a048-4cf95d479851
1f175aa6-4d9a-607c-a048-4cf95d479851
1f175aa6-4d9a-6144-a048-4cf95d479851
1f175aa6-4d9a-620c-a048-4cf95d479851
1f175aa6-4d9a-62d4-a048-4cf95d479851
1f175aa6-4d9a-6392-a048-4cf95d479851
1f175aa6-4d9a-6450-a048-4cf95d479851
1f175aa6-4d9a-650e-a048-4cf95d479851
1f175aa6-4d9a-65cc-a048-4cf95d479851
1f175aa6-4d9a-6716-a048-4cf95d479851
1f175aa6-4d9a-67de-a048-4cf95d479851
1f175aa6-4d9a-689c-a048-4cf95d479851
1f175aa6-4d9a-6964-a048-4cf95d479851
1f175aa6-4d9a-6a22-a048-4cf95d479851

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)

64d9aaf4-75aa-11f1-a048-4cf95d479851
64d9ab58-75aa-11f1-a048-4cf95d479851
64d9abb2-75aa-11f1-a048-4cf95d479851
64d9ac16-75aa-11f1-a048-4cf95d479851
64d9ac70-75aa-11f1-a048-4cf95d479851
64d9acd4-75aa-11f1-a048-4cf95d479851
64d9ad38-75aa-11f1-a048-4cf95d479851
64d9ad92-75aa-11f1-a048-4cf95d479851
64d9adec-75aa-11f1-a048-4cf95d479851
64d9ae50-75aa-11f1-a048-4cf95d479851
64d9aeaa-75aa-11f1-a048-4cf95d479851
64d9af0e-75aa-11f1-a048-4cf95d479851
64d9af72-75aa-11f1-a048-4cf95d479851
64d9afd6-75aa-11f1-a048-4cf95d479851
64d9b026-75aa-11f1-a048-4cf95d479851

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)

b3d7350c-0b00-870b-87ea-5ce32bd83b97
9c42360c-0b00-870b-87ea-5ce32bd83b97
7737370c-0b00-870b-87ea-5ce32bd83b97
e8e8380c-0b00-870b-87ea-5ce32bd83b97
ed34390c-0b00-870b-87ea-5ce32bd83b97
46033a0c-0b00-870b-87ea-5ce32bd83b97
ce3c3b0c-0b00-870b-87ea-5ce32bd83b97
dd4d3c0c-0b00-870b-87ea-5ce32bd83b97
f3db3d0c-0b00-870b-87ea-5ce32bd83b97
76403e0c-0b00-870b-87ea-5ce32bd83b97
9e943f0c-0b00-870b-87ea-5ce32bd83b97
3206400c-0b00-870b-87ea-5ce32bd83b97
1eb3410c-0b00-870b-87ea-5ce32bd83b97
5143420c-0b00-870b-87ea-5ce32bd83b97
0e09430c-0b00-870b-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)

8afdcae1-48e9-4524-be91-2ab78e3fcab1
223f0db6-fd54-4860-b23d-1817aca42b91
4449bb18-3e87-4e88-8592-e9035915ca1c
60c0f0d7-d71a-45a4-90ea-4815b0ec0ff6
b3b7219c-dd1f-4185-9922-e81d55ef8e1f
643f29fa-d386-40ca-86b5-12c1e410b8c4
9dfa4daf-6d2e-43a7-81a5-a72f22fb051d
a548566b-9bda-478a-b382-cde513db3145
09bb5ac8-50b6-40e8-863a-97b12d61e8eb
f77ffb7d-8c2b-41b0-8063-fd9fc021cec1
e125ee48-1713-4e52-87c3-942477eb647b
93424ef9-4f6f-4096-95cd-3a34cdc08879
329b5030-fbd3-4d30-a790-adedd95ea0b9
64b0ce4f-169e-4e47-84ce-10dbc85e9992
47260c72-7f31-471c-9eff-0e3b487907ed

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: