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)

01934d9e-08ef-78ee-80f3-4afd7a39f523
01934d9e-08ef-7a84-9f92-cafabdb47914
01934d9e-08ef-7bbf-9aa4-b78bd5d7901f
01934d9e-08ef-7ce6-9a9a-0a3697dda012
01934d9e-08ef-7e00-87d8-fccaef9161cf
01934d9e-08ef-7f1f-9736-38b6717aba65
01934d9e-08f0-703a-aa9c-442ae34e40c7
01934d9e-08f0-718e-b4a2-94353a0a4fda
01934d9e-08f0-72ad-a058-f13f1be565ae
01934d9e-08f0-73c7-be86-1aeda07c1f9d
01934d9e-08f0-74e6-a239-ab27382bb6a9
01934d9e-08f0-7605-a859-b8872492bbc4
01934d9e-08f0-7723-9492-47e9e29b8e99
01934d9e-08f0-783e-8c25-37139a87f277
01934d9e-08f0-795d-ba1c-b38792c17141

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)

1efa7da0-0be7-69b8-83dc-4cf95d479851
1efa7da0-0be7-6b34-83dc-4cf95d479851
1efa7da0-0be7-6c1a-83dc-4cf95d479851
1efa7da0-0be7-6cec-83dc-4cf95d479851
1efa7da0-0be7-6dbe-83dc-4cf95d479851
1efa7da0-0be7-6e7c-83dc-4cf95d479851
1efa7da0-0be7-6f44-83dc-4cf95d479851
1efa7da0-0be8-600c-83dc-4cf95d479851
1efa7da0-0be8-60ca-83dc-4cf95d479851
1efa7da0-0be8-6192-83dc-4cf95d479851
1efa7da0-0be8-62c8-83dc-4cf95d479851
1efa7da0-0be8-639a-83dc-4cf95d479851
1efa7da0-0be8-6462-83dc-4cf95d479851
1efa7da0-0be8-6520-83dc-4cf95d479851
1efa7da0-0be8-65de-83dc-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)

a0b06d5b-6074-464f-aa63-92209a8d3b8b
75ef9a31-c6cf-4b09-ab85-6477921098a9
a68b689b-7180-4255-ac2c-deb419fb469c
3a8ff04d-90a6-4440-bb04-902e2ffd7a8e
bd03faa7-4d8f-4c8b-ad21-023e07df18db
f29ffdc2-c078-4336-b371-bf9d9c6dc6af
7f7f0d82-cc75-41da-a520-ab1ebc7db05f
758b9cd6-88f2-4f58-aa26-bd2f4838f6cf
3c1e4ee5-660f-4082-abb2-deef1b179d06
cfb47ad1-f246-493d-a71d-fadf7e47cdc8
d755e8e5-b2f4-4844-bee7-0610e49cc833
92aa9b4d-7d04-4944-8306-a831c0100c0e
fa1cd647-ab40-4f54-8943-2600710313f0
d534f7b1-0f3d-4ac3-ae5d-a372a071f73f
9948105d-4216-4832-9e00-00072ef40b24

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)

00be8b10-a7da-11ef-83dc-4cf95d479851
00be8b74-a7da-11ef-83dc-4cf95d479851
00be8bce-a7da-11ef-83dc-4cf95d479851
00be8c32-a7da-11ef-83dc-4cf95d479851
00be8c8c-a7da-11ef-83dc-4cf95d479851
00be8cf0-a7da-11ef-83dc-4cf95d479851
00be8d4a-a7da-11ef-83dc-4cf95d479851
00be8dae-a7da-11ef-83dc-4cf95d479851
00be8e12-a7da-11ef-83dc-4cf95d479851
00be8e76-a7da-11ef-83dc-4cf95d479851
00be8ee4-a7da-11ef-83dc-4cf95d479851
00be8f48-a7da-11ef-83dc-4cf95d479851
00be8fac-a7da-11ef-83dc-4cf95d479851
00be9006-a7da-11ef-83dc-4cf95d479851
00be906a-a7da-11ef-83dc-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

2627e502-01c0-8146-87e8-5ce32bd83b96
7a41e602-01c0-8146-87e8-5ce32bd83b96
8574e702-01c0-8146-87e8-5ce32bd83b96
8f4ae802-01c0-8146-87e8-5ce32bd83b96
301ee902-01c0-8146-87e8-5ce32bd83b96
48a6ea02-01c0-8146-87e8-5ce32bd83b96
e055eb02-01c0-8146-87e8-5ce32bd83b96
8c5dec02-01c0-8146-87e8-5ce32bd83b96
3728ed02-01c0-8146-87e8-5ce32bd83b96
7f27ee02-01c0-8146-87e8-5ce32bd83b96
b6d3ef02-01c0-8146-87e8-5ce32bd83b96
cd81f002-01c0-8146-87e8-5ce32bd83b96
e131f102-01c0-8146-87e8-5ce32bd83b96
595ff202-01c0-8146-87e8-5ce32bd83b96
9535f402-01c0-8146-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: