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)

019c968d-36c3-7fe8-8774-e54299515e21
019c968d-36c4-71d3-94d8-f1fdafd56575
019c968d-36c4-7317-933a-b1f08a552776
019c968d-36c4-743a-bd46-64a42d500ad4
019c968d-36c4-7559-98a0-d6794a902f2e
019c968d-36c4-7677-996d-a66db6a5fa16
019c968d-36c4-7796-8d85-e9b52d2c18aa
019c968d-36c4-78b1-9ab8-94479525a80b
019c968d-36c4-79cf-8416-4194f2b00598
019c968d-36c4-7aee-8e2f-e2fb605e38a2
019c968d-36c4-7c09-a00d-a6ddc357bd08
019c968d-36c4-7d27-8b03-0f5d7ff95063
019c968d-36c4-7e42-adcd-624d7c8021fc
019c968d-36c4-7f5d-a26e-60cc1918ad00
019c968d-36c5-707b-9be6-e92dc23b7ee0

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)

1f1128af-facb-64aa-9e46-4cf95d479851
1f1128af-facb-664e-9e46-4cf95d479851
1f1128af-facb-672a-9e46-4cf95d479851
1f1128af-facb-6806-9e46-4cf95d479851
1f1128af-facb-68ce-9e46-4cf95d479851
1f1128af-facb-6996-9e46-4cf95d479851
1f1128af-facb-6a5e-9e46-4cf95d479851
1f1128af-facb-6b26-9e46-4cf95d479851
1f1128af-facb-6bee-9e46-4cf95d479851
1f1128af-facb-6cac-9e46-4cf95d479851
1f1128af-facb-6de2-9e46-4cf95d479851
1f1128af-facb-6eb4-9e46-4cf95d479851
1f1128af-facb-6f7c-9e46-4cf95d479851
1f1128af-facc-603a-9e46-4cf95d479851
1f1128af-facc-6102-9e46-4cf95d479851

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)

ec7fd3fc-4af4-412e-a737-f22a1ae578a3
a06e6ddb-548f-4df2-9e94-bfc564dcbdd7
0bfc3368-713a-43ae-a1ec-86fb898c706f
645e37e3-4a7d-4022-b0d0-2e5c55ea4990
005f038d-dd00-4a21-a1d0-c049606313cb
fc6fc689-946c-46c4-b447-b23ab89c28ae
21d32933-a6cf-4ba2-ad3a-551dc1ee29f5
5049f603-af48-4780-b184-8e2e3eb17cbe
a685b1ac-614c-45d5-b5c5-9b8e40015670
5ce8b1ee-8373-45b0-9527-0a55b7b6d35d
56cddb33-ec2a-46f9-953b-7d1285c5f7d5
05fae068-bb79-4eb3-aceb-5aa209acd5be
e758b8c6-ad29-41ef-a0d8-6e1527c9b9d6
15fca0b7-5e83-4373-a232-e80814b0a087
8892e485-ceb8-4f27-bb58-064f10ab0c56

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)

ffacc62a-128a-11f1-9e46-4cf95d479851
ffacc68e-128a-11f1-9e46-4cf95d479851
ffacc6f2-128a-11f1-9e46-4cf95d479851
ffacc756-128a-11f1-9e46-4cf95d479851
ffacc7b0-128a-11f1-9e46-4cf95d479851
ffacc814-128a-11f1-9e46-4cf95d479851
ffacc878-128a-11f1-9e46-4cf95d479851
ffacc8f0-128a-11f1-9e46-4cf95d479851
ffacc954-128a-11f1-9e46-4cf95d479851
ffacc9b8-128a-11f1-9e46-4cf95d479851
ffacca26-128a-11f1-9e46-4cf95d479851
ffacca80-128a-11f1-9e46-4cf95d479851
ffaccada-128a-11f1-9e46-4cf95d479851
ffaccb3e-128a-11f1-9e46-4cf95d479851
ffaccc10-128a-11f1-9e46-4cf95d479851

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)

2723f202-df04-8803-87ea-5ce32bd83b97
f963f302-df04-8803-87ea-5ce32bd83b97
19ebf502-df04-8803-87ea-5ce32bd83b97
3fa2f602-df04-8803-87ea-5ce32bd83b97
476bf702-df04-8803-87ea-5ce32bd83b97
147ff802-df04-8803-87ea-5ce32bd83b97
ab29f902-df04-8803-87ea-5ce32bd83b97
c071fa02-df04-8803-87ea-5ce32bd83b97
0d78fb02-df04-8803-87ea-5ce32bd83b97
6529fc02-df04-8803-87ea-5ce32bd83b97
cf2bfd02-df04-8803-87ea-5ce32bd83b97
0ae4fe02-df04-8803-87ea-5ce32bd83b97
f7f5ff02-df04-8803-87ea-5ce32bd83b97
f5800103-df04-8803-87ea-5ce32bd83b97
164c0203-df04-8803-87ea-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: