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)

019f9c6b-e0c2-791f-a860-f6d6690ebf03
019f9c6b-e0c2-7b38-997e-850c7d96e719
019f9c6b-e0c2-7c77-bfe3-f091f0ac1c95
019f9c6b-e0c2-7d96-b7ce-7543f9d7f772
019f9c6b-e0c2-7ead-81af-4084a39cdb56
019f9c6b-e0c2-7fc3-947d-f2f4dfd5cf11
019f9c6b-e0c3-70da-bd31-ce75f2ded034
019f9c6b-e0c3-71f0-b5d8-7b176b9fe23e
019f9c6b-e0c3-7303-b741-b1383281c9b0
019f9c6b-e0c3-7419-a28f-3de37d3da832
019f9c6b-e0c3-7534-87f1-073fb929bd79
019f9c6b-e0c3-764a-9e0a-20d2a59a89ec
019f9c6b-e0c3-7761-9ac6-6ae9c45d6910
019f9c6b-e0c3-7877-bd6f-7a2f5cef3e4a
019f9c6b-e0c3-798a-86ae-ef6e18436df7

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)

1f188a04-97d1-6e86-92b0-4cf95d479851
1f188a04-97d2-6052-92b0-4cf95d479851
1f188a04-97d2-612e-92b0-4cf95d479851
1f188a04-97d2-61f6-92b0-4cf95d479851
1f188a04-97d2-62b4-92b0-4cf95d479851
1f188a04-97d2-6372-92b0-4cf95d479851
1f188a04-97d2-6430-92b0-4cf95d479851
1f188a04-97d2-64e4-92b0-4cf95d479851
1f188a04-97d2-65a2-92b0-4cf95d479851
1f188a04-97d2-6660-92b0-4cf95d479851
1f188a04-97d2-67a0-92b0-4cf95d479851
1f188a04-97d2-6868-92b0-4cf95d479851
1f188a04-97d2-6926-92b0-4cf95d479851
1f188a04-97d2-69e4-92b0-4cf95d479851
1f188a04-97d2-6a98-92b0-4cf95d479851

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)

497d2b6a-88a0-11f1-92b0-4cf95d479851
497d2bc4-88a0-11f1-92b0-4cf95d479851
497d2c28-88a0-11f1-92b0-4cf95d479851
497d2c82-88a0-11f1-92b0-4cf95d479851
497d2ce6-88a0-11f1-92b0-4cf95d479851
497d2d40-88a0-11f1-92b0-4cf95d479851
497d2dae-88a0-11f1-92b0-4cf95d479851
497d2e12-88a0-11f1-92b0-4cf95d479851
497d2e6c-88a0-11f1-92b0-4cf95d479851
497d2ec6-88a0-11f1-92b0-4cf95d479851
497d2f2a-88a0-11f1-92b0-4cf95d479851
497d2f98-88a0-11f1-92b0-4cf95d479851
497d2ffc-88a0-11f1-92b0-4cf95d479851
497d3060-88a0-11f1-92b0-4cf95d479851
497d30ba-88a0-11f1-92b0-4cf95d479851

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)

030f6d2b-c400-8f0c-87ea-5ce32bd83b97
585f6e2b-c400-8f0c-87ea-5ce32bd83b97
96fa6f2b-c400-8f0c-87ea-5ce32bd83b97
2b31702b-c400-8f0c-87ea-5ce32bd83b97
887a712b-c400-8f0c-87ea-5ce32bd83b97
677d722b-c400-8f0c-87ea-5ce32bd83b97
b62d732b-c400-8f0c-87ea-5ce32bd83b97
e9f1742b-c400-8f0c-87ea-5ce32bd83b97
1669752b-c400-8f0c-87ea-5ce32bd83b97
c3d5762b-c400-8f0c-87ea-5ce32bd83b97
b58f782b-c400-8f0c-87ea-5ce32bd83b97
d0df792b-c400-8f0c-87ea-5ce32bd83b97
84937a2b-c400-8f0c-87ea-5ce32bd83b97
3fe47b2b-c400-8f0c-87ea-5ce32bd83b97
4dd57c2b-c400-8f0c-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)

9861e74f-e0de-480d-8e91-19a65b52fd26
2820245b-e324-4ff7-af03-04670abb16f6
20b294ef-f233-429c-ba47-65630ab1f497
be587ed1-6884-4102-a97d-0ab5a6829076
0b4c734e-9d74-42be-a43c-87d732774eb7
b410787b-3bbd-43d1-be2c-e1a898d25aee
40e97a53-6b13-443e-9105-7541b32996de
a349721d-e19a-45d3-b888-ea4e461c0b1d
f890cdd0-93da-46bc-9ce1-95712f6d6d7a
22f89fca-31f9-4cec-b15e-65ec020fac79
de55b07b-e0cd-406f-81f7-4ad9a5ead245
68b2b8a2-c919-4711-9bc4-6aedc40c4a7f
fa6652cb-6526-4250-8fba-46500890afbc
43e9a7fe-1b1e-4f1e-9711-75e198ebef9e
1852bdb3-465e-441e-b73b-e0ac04a0a0b2

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: