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)

019bb4a4-45f7-734c-a40d-f9d54c5f2d3c
019bb4a4-45f7-750b-ac80-d5202526f76c
019bb4a4-45f7-764a-9a01-6a4286635c38
019bb4a4-45f7-776d-88bb-ff189f325212
019bb4a4-45f7-7888-8018-73eddd32dcd5
019bb4a4-45f7-79a2-976e-f8c7e1aff8d9
019bb4a4-45f7-7abd-a6cb-73afdbc7fcde
019bb4a4-45f7-7bd8-9a1a-055bf0903f33
019bb4a4-45f7-7cee-810a-d47eb6e7b106
019bb4a4-45f7-7e09-a9d8-7a51ce678041
019bb4a4-45f7-7f1f-a773-cf64a8be0c9e
019bb4a4-45f8-703a-aa4e-a8a4d6addcab
019bb4a4-45f8-7154-aac6-35a88d9f67fb
019bb4a4-45f8-726f-93ed-0cd38e983fda
019bb4a4-45f8-7386-a2b2-2ab1dd8ea815

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)

1f0f0126-46e7-6554-9754-4cf95d479851
1f0f0126-46e7-66f8-9754-4cf95d479851
1f0f0126-46e7-67d4-9754-4cf95d479851
1f0f0126-46e7-68b0-9754-4cf95d479851
1f0f0126-46e7-6978-9754-4cf95d479851
1f0f0126-46e7-6a40-9754-4cf95d479851
1f0f0126-46e7-6b08-9754-4cf95d479851
1f0f0126-46e7-6bc6-9754-4cf95d479851
1f0f0126-46e7-6c8e-9754-4cf95d479851
1f0f0126-46e7-6d4c-9754-4cf95d479851
1f0f0126-46e7-6e8c-9754-4cf95d479851
1f0f0126-46e7-6f5e-9754-4cf95d479851
1f0f0126-46e8-601c-9754-4cf95d479851
1f0f0126-46e8-60da-9754-4cf95d479851
1f0f0126-46e8-618e-9754-4cf95d479851

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)

ff44f23f-336e-4fb3-98ed-78cac1fa89d3
dc180bdf-4462-4faa-b85e-a059f9549fbe
345e3731-4b23-4d2b-9b50-c735d8eefd29
4a598aa7-3589-4d08-ae77-5767bb5c7714
9fb5b77b-bb8b-4a89-8e19-d4d1cf5a3521
ab6b607a-3c75-4dc1-ac02-6e83e7d57859
fb36de04-c0b4-4eea-92ff-271c68bc8115
eb282659-0ec2-4f57-ad71-d2d2d279a017
312ad743-e8ae-4ae2-a0ff-ed099730c1da
11dc7ab9-9344-4cfd-bf58-79c279d6a00a
1bab1938-72fd-4d5d-af04-07320e40e945
796e4b40-2769-4afc-9618-0651b75b6835
2efdd93c-f8fd-4219-89de-7377a2a6daf9
f55d461d-424b-417d-aed8-27ad745837ec
e61bb79c-0a95-4227-9164-8e70fe9702f0

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)

646e86b6-f012-11f0-9754-4cf95d479851
646e871a-f012-11f0-9754-4cf95d479851
646e877e-f012-11f0-9754-4cf95d479851
646e87ec-f012-11f0-9754-4cf95d479851
646e8850-f012-11f0-9754-4cf95d479851
646e88b4-f012-11f0-9754-4cf95d479851
646e8918-f012-11f0-9754-4cf95d479851
646e897c-f012-11f0-9754-4cf95d479851
646e89ea-f012-11f0-9754-4cf95d479851
646e8a4e-f012-11f0-9754-4cf95d479851
646e8abc-f012-11f0-9754-4cf95d479851
646e8b16-f012-11f0-9754-4cf95d479851
646e8b84-f012-11f0-9754-4cf95d479851
646e8bde-f012-11f0-9754-4cf95d479851
646e8c42-f012-11f0-9754-4cf95d479851

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)

00535a03-9e05-8c00-87ea-5ce32bd83b97
91495b03-9e05-8c00-87ea-5ce32bd83b97
28fd5c03-9e05-8c00-87ea-5ce32bd83b97
89025d03-9e05-8c00-87ea-5ce32bd83b97
53855e03-9e05-8c00-87ea-5ce32bd83b97
376d5f03-9e05-8c00-87ea-5ce32bd83b97
06866003-9e05-8c00-87ea-5ce32bd83b97
a90f6103-9e05-8c00-87ea-5ce32bd83b97
edd26203-9e05-8c00-87ea-5ce32bd83b97
1bc06303-9e05-8c00-87ea-5ce32bd83b97
b6246403-9e05-8c00-87ea-5ce32bd83b97
eb976503-9e05-8c00-87ea-5ce32bd83b97
e09a6603-9e05-8c00-87ea-5ce32bd83b97
78466703-9e05-8c00-87ea-5ce32bd83b97
603e6803-9e05-8c00-87ea-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: