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)

019b703c-edd5-7c29-8a20-0574d8e4b586
019b703c-edd5-7dd3-a13e-e3ca95ef45b2
019b703c-edd5-7f13-97bc-8c2a0e53177a
019b703c-edd6-7032-b179-71c87b5b206e
019b703c-edd6-714c-9894-87b96d675600
019b703c-edd6-7267-9eb6-672a81b266a6
019b703c-edd6-737d-96c1-aee357e619c6
019b703c-edd6-7498-b78c-3b3db14520d0
019b703c-edd6-75af-8e52-11df46ccf146
019b703c-edd6-76cd-8c6f-f6071a47ed4e
019b703c-edd6-77e8-8b48-8880454568c4
019b703c-edd6-78fe-aba8-866204be000b
019b703c-edd6-7a15-b72b-13ab9c17655b
019b703c-edd6-7b30-9816-c818b8ab2af2
019b703c-edd6-7c46-8307-21b30711de99

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)

1f0e5a25-f8bd-6a7e-9046-4cf95d479851
1f0e5a25-f8bd-6c04-9046-4cf95d479851
1f0e5a25-f8bd-6cea-9046-4cf95d479851
1f0e5a25-f8bd-6dbc-9046-4cf95d479851
1f0e5a25-f8bd-6e7a-9046-4cf95d479851
1f0e5a25-f8bd-6f42-9046-4cf95d479851
1f0e5a25-f8be-600a-9046-4cf95d479851
1f0e5a25-f8be-60c8-9046-4cf95d479851
1f0e5a25-f8be-6186-9046-4cf95d479851
1f0e5a25-f8be-624e-9046-4cf95d479851
1f0e5a25-f8be-6384-9046-4cf95d479851
1f0e5a25-f8be-6456-9046-4cf95d479851
1f0e5a25-f8be-651e-9046-4cf95d479851
1f0e5a25-f8be-65dc-9046-4cf95d479851
1f0e5a25-f8be-669a-9046-4cf95d479851

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)

3990b6a6-0c07-46d7-ada0-a59431ae1e2c
40231b40-4e6c-4b99-a0cc-fbe6c839b2f9
d7df9fe2-cc26-4902-99d2-e361b17641a8
f09c6b09-83ca-4f15-975e-aaabca98bd9e
beb439f0-8577-4630-99f5-9824c98c4946
b9c0cd57-4849-448f-9c87-334d76416517
00007497-9b8e-4b4c-b567-b03803a94e24
49c264d1-3f93-4f02-84ae-e8c711a245a1
4e46d190-f7c0-4921-952e-28b7364339b1
1b907e79-c193-49e6-9d33-1613277e6034
27dfb791-c216-41a6-9086-b493ab8a9ad0
14040871-02c3-4429-b2f0-f012e2e161ca
4f7f8d7a-cfe7-41e8-b7e8-5a5e5faea570
3e7364f8-c834-4faa-8224-a83eec0ee92a
a7562533-339b-42ce-b8d5-0f5ab61c3b21

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)

5f8bebae-e5a2-11f0-9046-4cf95d479851
5f8bec12-e5a2-11f0-9046-4cf95d479851
5f8bec76-e5a2-11f0-9046-4cf95d479851
5f8becda-e5a2-11f0-9046-4cf95d479851
5f8bed3e-e5a2-11f0-9046-4cf95d479851
5f8bed98-e5a2-11f0-9046-4cf95d479851
5f8bedfc-e5a2-11f0-9046-4cf95d479851
5f8bee60-e5a2-11f0-9046-4cf95d479851
5f8beeba-e5a2-11f0-9046-4cf95d479851
5f8bef1e-e5a2-11f0-9046-4cf95d479851
5f8bef82-e5a2-11f0-9046-4cf95d479851
5f8befe6-e5a2-11f0-9046-4cf95d479851
5f8bf054-e5a2-11f0-9046-4cf95d479851
5f8bf0c2-e5a2-11f0-9046-4cf95d479851
5f8bf126-e5a2-11f0-9046-4cf95d479851

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)

f4dce43b-0604-8c16-87e9-5ce32bd83b97
693ce53b-0604-8c16-87e9-5ce32bd83b97
c280e63b-0604-8c16-87e9-5ce32bd83b97
01a4e83b-0604-8c16-87e9-5ce32bd83b97
ac70e93b-0604-8c16-87e9-5ce32bd83b97
cfe3ea3b-0604-8c16-87e9-5ce32bd83b97
c891eb3b-0604-8c16-87e9-5ce32bd83b97
0a02ec3b-0604-8c16-87e9-5ce32bd83b97
4db6ed3b-0604-8c16-87e9-5ce32bd83b97
23beee3b-0604-8c16-87e9-5ce32bd83b97
1a9aef3b-0604-8c16-87e9-5ce32bd83b97
ebf2f03b-0604-8c16-87e9-5ce32bd83b97
cef7f13b-0604-8c16-87e9-5ce32bd83b97
5b95f23b-0604-8c16-87e9-5ce32bd83b97
4745f33b-0604-8c16-87e9-5ce32bd83b97

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

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: