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)

019ccb9e-02f2-7950-9c5d-b1ed106216a9
019ccb9e-02f2-7aea-87f0-099ef36173bf
019ccb9e-02f2-7c25-967f-8a744f874e05
019ccb9e-02f2-7d44-9bf9-061341af3863
019ccb9e-02f2-7e1d-a045-0acd779f3ef8
019ccb9e-02f2-7f3c-89f3-838a93917dc7
019ccb9e-02f3-7052-96ad-26481bd4f87b
019ccb9e-02f3-716d-94cd-3df3db22e57e
019ccb9e-02f3-7288-b939-23bf39759262
019ccb9e-02f3-739e-8a16-9e4cacaf6b9b
019ccb9e-02f3-74b5-810d-1b6d2cabc3b9
019ccb9e-02f3-75cb-8fe4-6a6be5308543
019ccb9e-02f3-76e2-aa03-ae146ca83ba0
019ccb9e-02f3-77fc-91fa-9281b487f20b
019ccb9e-02f3-7913-b4d7-86f7f4bb5bed

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)

1f11aa3d-fd48-6e16-8294-4cf95d479851
1f11aa3d-fd48-6f88-8294-4cf95d479851
1f11aa3d-fd49-6064-8294-4cf95d479851
1f11aa3d-fd49-6122-8294-4cf95d479851
1f11aa3d-fd49-61e0-8294-4cf95d479851
1f11aa3d-fd49-629e-8294-4cf95d479851
1f11aa3d-fd49-635c-8294-4cf95d479851
1f11aa3d-fd49-641a-8294-4cf95d479851
1f11aa3d-fd49-64ce-8294-4cf95d479851
1f11aa3d-fd49-658c-8294-4cf95d479851
1f11aa3d-fd49-66c2-8294-4cf95d479851
1f11aa3d-fd49-678a-8294-4cf95d479851
1f11aa3d-fd49-6848-8294-4cf95d479851
1f11aa3d-fd49-68fc-8294-4cf95d479851
1f11aa3d-fd49-69ba-8294-4cf95d479851

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)

f09a7c87-2a9b-47a3-8b9a-3c9ec84a4d3d
0bb4f738-11b1-4d12-9426-32dad79ebbd8
20db383a-1ecf-4ebf-980f-c73edc009305
69c4f459-d81a-43f3-ba12-6bd07a648ef7
55643513-515d-4a3b-8e36-9c72017254a0
a52b741c-0943-4452-b51c-05fbd308ae09
ffecab84-9cf2-44d8-a83b-8d6c102a26c5
f22adfbb-3024-425a-bdb5-13518cef65a2
e2066334-e75d-4aeb-8ade-2d473bf2fa7d
fe7ba5af-1c75-4d64-af0c-9066f3a538a1
0a53ca32-282f-4c02-994b-324e53ac9f98
97f535e4-c01e-4803-93e5-4d415c78dd14
c411f612-895d-4873-ac8a-4079f009a6d5
d8fba805-1022-4abf-86e8-494bfba2d505
6310443b-6ecb-4ac6-b978-45bc1dd52e0e

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)

dfd49ece-1aa3-11f1-8294-4cf95d479851
dfd49f28-1aa3-11f1-8294-4cf95d479851
dfd49f8c-1aa3-11f1-8294-4cf95d479851
dfd49fe6-1aa3-11f1-8294-4cf95d479851
dfd4a040-1aa3-11f1-8294-4cf95d479851
dfd4a09a-1aa3-11f1-8294-4cf95d479851
dfd4a0fe-1aa3-11f1-8294-4cf95d479851
dfd4a158-1aa3-11f1-8294-4cf95d479851
dfd4a1b2-1aa3-11f1-8294-4cf95d479851
dfd4a20c-1aa3-11f1-8294-4cf95d479851
dfd4a266-1aa3-11f1-8294-4cf95d479851
dfd4a2c0-1aa3-11f1-8294-4cf95d479851
dfd4a31a-1aa3-11f1-8294-4cf95d479851
dfd4a37e-1aa3-11f1-8294-4cf95d479851
dfd4a3e2-1aa3-11f1-8294-4cf95d479851

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)

c95e3e10-f500-8304-87ea-5ce32bd83b97
902c3f10-f500-8304-87ea-5ce32bd83b97
a3b14010-f500-8304-87ea-5ce32bd83b97
f5754110-f500-8304-87ea-5ce32bd83b97
8db84210-f500-8304-87ea-5ce32bd83b97
9fbb4310-f500-8304-87ea-5ce32bd83b97
12b04410-f500-8304-87ea-5ce32bd83b97
6dae4510-f500-8304-87ea-5ce32bd83b97
949f4610-f500-8304-87ea-5ce32bd83b97
5ed34710-f500-8304-87ea-5ce32bd83b97
176a4810-f500-8304-87ea-5ce32bd83b97
285c4a10-f500-8304-87ea-5ce32bd83b97
c63f4b10-f500-8304-87ea-5ce32bd83b97
65a94c10-f500-8304-87ea-5ce32bd83b97
3f9b4d10-f500-8304-87ea-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

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: