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)

01984a6a-9aba-7863-8a98-c2a4febcd5a6
01984a6a-9aba-79fc-a8cb-b77f5835f53e
01984a6a-9aba-7b40-9a11-242f53c421d6
01984a6a-9aba-7c67-b1f3-b593f4a04d22
01984a6a-9aba-7d86-866f-a9a4577b15b3
01984a6a-9aba-7ea4-ad83-003fee96a12d
01984a6a-9aba-7fc3-aab7-7f74862cdccf
01984a6a-9abb-70e2-a90d-a4d380ff3a8f
01984a6a-9abb-7200-83f8-ea4950665951
01984a6a-9abb-731b-b888-b117bce1bb78
01984a6a-9abb-743a-8a5e-a64beab2c4b9
01984a6a-9abb-7559-8e64-281651bbf5c3
01984a6a-9abb-766f-b647-6514875ca450
01984a6a-9abb-7792-986c-e7efaca63c49
01984a6a-9abb-78b1-b2a6-7fdd4eb37387

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)

1f06aacf-7bd8-61c4-b132-4cf95d479851
1f06aacf-7bd8-6372-b132-4cf95d479851
1f06aacf-7bd8-6458-b132-4cf95d479851
1f06aacf-7bd8-6534-b132-4cf95d479851
1f06aacf-7bd8-65f2-b132-4cf95d479851
1f06aacf-7bd8-66ba-b132-4cf95d479851
1f06aacf-7bd8-6782-b132-4cf95d479851
1f06aacf-7bd8-684a-b132-4cf95d479851
1f06aacf-7bd8-6908-b132-4cf95d479851
1f06aacf-7bd8-69c6-b132-4cf95d479851
1f06aacf-7bd8-6b10-b132-4cf95d479851
1f06aacf-7bd8-6be2-b132-4cf95d479851
1f06aacf-7bd8-6caa-b132-4cf95d479851
1f06aacf-7bd8-6d5e-b132-4cf95d479851
1f06aacf-7bd8-6e1c-b132-4cf95d479851

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)

2c59fd93-a5d3-4ee4-b356-6a7f10130bbf
b267134b-ee97-4d49-a2f9-87fba615a46f
3449f6dd-7a8a-46fe-a0a6-5b8eb6a0d42f
a7a1e114-5ca3-405b-bd0f-51b1ae440a21
e250d1cc-9521-45b5-a31f-147afedc1d0a
be535b01-a010-4a14-a52d-b6b3ebc56670
2105c692-8068-4bbc-ada4-29432dfb5019
bc633483-ba87-475b-9fc8-157889d85c96
fb9f0563-4d81-4b8e-9c14-9aab5ae9e36f
089d0b56-2934-4531-8a1e-7deed3dc89ed
70355e97-beb1-47aa-9b93-e95afe734ef5
e1a157d4-da82-47ea-b644-ab4192ed9a6c
29e49abc-eaf6-46c3-92d7-65e48b123ae5
b484d6b8-7f69-4025-94a7-69b1073300e8
75376b1f-b183-408c-b516-30e542465944

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)

f7bd933a-6aac-11f0-b132-4cf95d479851
f7bd93a8-6aac-11f0-b132-4cf95d479851
f7bd9402-6aac-11f0-b132-4cf95d479851
f7bd9466-6aac-11f0-b132-4cf95d479851
f7bd94ca-6aac-11f0-b132-4cf95d479851
f7bd952e-6aac-11f0-b132-4cf95d479851
f7bd9592-6aac-11f0-b132-4cf95d479851
f7bd95f6-6aac-11f0-b132-4cf95d479851
f7bd965a-6aac-11f0-b132-4cf95d479851
f7bd96b4-6aac-11f0-b132-4cf95d479851
f7bd9718-6aac-11f0-b132-4cf95d479851
f7bd9786-6aac-11f0-b132-4cf95d479851
f7bd97e0-6aac-11f0-b132-4cf95d479851
f7bd9844-6aac-11f0-b132-4cf95d479851
f7bd989e-6aac-11f0-b132-4cf95d479851

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)

1daf2e39-5a01-800d-87e9-5ce32bd83b97
3a852f39-5a01-800d-87e9-5ce32bd83b97
78d33039-5a01-800d-87e9-5ce32bd83b97
fc223139-5a01-800d-87e9-5ce32bd83b97
06d43239-5a01-800d-87e9-5ce32bd83b97
56053339-5a01-800d-87e9-5ce32bd83b97
0e9b3439-5a01-800d-87e9-5ce32bd83b97
79563539-5a01-800d-87e9-5ce32bd83b97
71743639-5a01-800d-87e9-5ce32bd83b97
660b3739-5a01-800d-87e9-5ce32bd83b97
aa483839-5a01-800d-87e9-5ce32bd83b97
c7b23939-5a01-800d-87e9-5ce32bd83b97
d5903a39-5a01-800d-87e9-5ce32bd83b97
99253b39-5a01-800d-87e9-5ce32bd83b97
d4973c39-5a01-800d-87e9-5ce32bd83b97

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

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: