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)

019b2eb0-403e-7a2e-bcae-a6da9bac01ad
019b2eb0-403e-7be8-9a2e-c211ed2b0a43
019b2eb0-403e-7d2c-8460-84d67a15eb0d
019b2eb0-403e-7eb1-8166-c41c526b6694
019b2eb0-403e-7ff0-b3cc-5d103681a7d3
019b2eb0-403f-710b-8065-13848bf61f12
019b2eb0-403f-7225-99fe-d60ab84f7286
019b2eb0-403f-7340-8d7d-cfb9b732eae5
019b2eb0-403f-7457-875a-1d944eb57b7a
019b2eb0-403f-756d-9eba-2fb4c5a3b2e1
019b2eb0-403f-7688-8594-0569899e69ec
019b2eb0-403f-77a2-bbd8-5e2378341b04
019b2eb0-403f-78bd-bad1-c95ec5b22326
019b2eb0-403f-79dc-b577-297182328d9a
019b2eb0-403f-7af6-9ee1-fa6cf54abfd7

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)

1f0dba1d-84ef-6cbc-8edc-4cf95d479851
1f0dba1d-84ef-6e60-8edc-4cf95d479851
1f0dba1d-84ef-6f3c-8edc-4cf95d479851
1f0dba1d-84f0-6004-8edc-4cf95d479851
1f0dba1d-84f0-60cc-8edc-4cf95d479851
1f0dba1d-84f0-6180-8edc-4cf95d479851
1f0dba1d-84f0-623e-8edc-4cf95d479851
1f0dba1d-84f0-62fc-8edc-4cf95d479851
1f0dba1d-84f0-63b0-8edc-4cf95d479851
1f0dba1d-84f0-646e-8edc-4cf95d479851
1f0dba1d-84f0-65a4-8edc-4cf95d479851
1f0dba1d-84f0-666c-8edc-4cf95d479851
1f0dba1d-84f0-6720-8edc-4cf95d479851
1f0dba1d-84f0-67de-8edc-4cf95d479851
1f0dba1d-84f0-6892-8edc-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)

5545521e-8540-4946-b5b8-1a99b69c491f
3c630cf9-8f9b-419e-8ea3-0fb22ac6992f
a9b8e20c-c9f5-4424-8796-eff1854bcab0
e484dfcd-0370-486b-9565-9ddab7cc6a7e
08420007-0a4e-462a-98dc-f109e74978e4
736c245f-845c-4e7e-93c3-038af4730b1b
b387840d-e47a-4978-812c-c5fae5615f25
afeb621c-cde3-42bc-afe6-638af4068370
084ee29c-9e0e-4c72-a882-e33b3639e681
a16696ac-7f03-46ff-a3b2-ce6f7e5779d7
82cf1fe3-fe11-4a94-aa89-c20a9674e8cc
51ec1b5d-f2b0-4c67-855d-6aee967c8f56
2a2b9240-9288-4cbb-91bc-91513fad69b9
acb8363a-af75-45c3-8afb-6d2f6367096e
86b6ba31-4a14-4c51-b99d-184eb9e3718d

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)

d84f0d9c-dba1-11f0-8edc-4cf95d479851
d84f0e00-dba1-11f0-8edc-4cf95d479851
d84f0e5a-dba1-11f0-8edc-4cf95d479851
d84f0eb4-dba1-11f0-8edc-4cf95d479851
d84f0f0e-dba1-11f0-8edc-4cf95d479851
d84f0f68-dba1-11f0-8edc-4cf95d479851
d84f0fc2-dba1-11f0-8edc-4cf95d479851
d84f1026-dba1-11f0-8edc-4cf95d479851
d84f1080-dba1-11f0-8edc-4cf95d479851
d84f10da-dba1-11f0-8edc-4cf95d479851
d84f1134-dba1-11f0-8edc-4cf95d479851
d84f1198-dba1-11f0-8edc-4cf95d479851
d84f11f2-dba1-11f0-8edc-4cf95d479851
d84f124c-dba1-11f0-8edc-4cf95d479851
d84f12a6-dba1-11f0-8edc-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)

f81f6001-8e05-8f15-87e9-5ce32bd83b97
01196101-8e05-8f15-87e9-5ce32bd83b97
610d6201-8e05-8f15-87e9-5ce32bd83b97
98516301-8e05-8f15-87e9-5ce32bd83b97
c1d56401-8e05-8f15-87e9-5ce32bd83b97
11386501-8e05-8f15-87e9-5ce32bd83b97
6ed46601-8e05-8f15-87e9-5ce32bd83b97
76d06701-8e05-8f15-87e9-5ce32bd83b97
cdac6801-8e05-8f15-87e9-5ce32bd83b97
83996901-8e05-8f15-87e9-5ce32bd83b97
df7c6a01-8e05-8f15-87e9-5ce32bd83b97
54f16b01-8e05-8f15-87e9-5ce32bd83b97
57766c01-8e05-8f15-87e9-5ce32bd83b97
e4d96e01-8e05-8f15-87e9-5ce32bd83b97
c6406f01-8e05-8f15-87e9-5ce32bd83b97

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: