UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019ee96d-ceeb-775d-810c-166d06f73c07
019ee96d-ceeb-7961-a888-4f86ca354294
019ee96d-ceeb-7aea-9da2-0651beffee48
019ee96d-ceeb-7c3a-bfa6-e184ca833090
019ee96d-ceeb-7d86-afe6-109b84dd8058
019ee96d-ceeb-7ee2-8ce5-dcaad4f7af7e
019ee96d-ceec-704a-a746-97ea5c6096bb
019ee96d-ceec-71af-82e5-41638ca771c4
019ee96d-ceec-730b-b804-8bd1cb03982c
019ee96d-ceec-745f-8a5a-db8edc532936
019ee96d-ceec-75aa-933b-3af3e57d83d5
019ee96d-ceec-7707-a3c7-25f6837028f2
019ee96d-ceec-7873-b8c8-a394523b822e
019ee96d-ceec-79dc-9d33-bc10b8bad5c3
019ee96d-ceec-7b3c-b8a3-a09dea304054

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)

1f16d506-4e44-630e-9e52-4cf95d479851
1f16d506-4e44-6584-9e52-4cf95d479851
1f16d506-4e44-6700-9e52-4cf95d479851
1f16d506-4e44-6868-9e52-4cf95d479851
1f16d506-4e44-69c6-9e52-4cf95d479851
1f16d506-4e44-6b2e-9e52-4cf95d479851
1f16d506-4e44-6c96-9e52-4cf95d479851
1f16d506-4e44-6dfe-9e52-4cf95d479851
1f16d506-4e44-6f7a-9e52-4cf95d479851
1f16d506-4e45-610a-9e52-4cf95d479851
1f16d506-4e45-6344-9e52-4cf95d479851
1f16d506-4e45-64d4-9e52-4cf95d479851
1f16d506-4e45-6646-9e52-4cf95d479851
1f16d506-4e45-67b8-9e52-4cf95d479851
1f16d506-4e45-692a-9e52-4cf95d479851

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)

64e45aba-6d50-11f1-9e52-4cf95d479851
64e45b64-6d50-11f1-9e52-4cf95d479851
64e45c04-6d50-11f1-9e52-4cf95d479851
64e45c9a-6d50-11f1-9e52-4cf95d479851
64e45d3a-6d50-11f1-9e52-4cf95d479851
64e45dd0-6d50-11f1-9e52-4cf95d479851
64e45e70-6d50-11f1-9e52-4cf95d479851
64e45f06-6d50-11f1-9e52-4cf95d479851
64e45fa6-6d50-11f1-9e52-4cf95d479851
64e46046-6d50-11f1-9e52-4cf95d479851
64e460e6-6d50-11f1-9e52-4cf95d479851
64e46186-6d50-11f1-9e52-4cf95d479851
64e4621c-6d50-11f1-9e52-4cf95d479851
64e462bc-6d50-11f1-9e52-4cf95d479851
64e46352-6d50-11f1-9e52-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

56374530-2202-8c0a-87ea-5ce32bd83b97
fed34630-2202-8c0a-87ea-5ce32bd83b97
b4784730-2202-8c0a-87ea-5ce32bd83b97
6c924830-2202-8c0a-87ea-5ce32bd83b97
241e4930-2202-8c0a-87ea-5ce32bd83b97
42414a30-2202-8c0a-87ea-5ce32bd83b97
bd3a4b30-2202-8c0a-87ea-5ce32bd83b97
33074c30-2202-8c0a-87ea-5ce32bd83b97
b6704d30-2202-8c0a-87ea-5ce32bd83b97
68fe4e30-2202-8c0a-87ea-5ce32bd83b97
a3fb4f30-2202-8c0a-87ea-5ce32bd83b97
d6ca5030-2202-8c0a-87ea-5ce32bd83b97
b3dd5130-2202-8c0a-87ea-5ce32bd83b97
dd7a5230-2202-8c0a-87ea-5ce32bd83b97
07605330-2202-8c0a-87ea-5ce32bd83b97

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)

0d3f9daa-78f8-43b9-b515-3baf1c15e4ec
83f93031-38e0-4f92-a2d6-dd2d03401e10
bd20878a-38e7-4e64-9e3e-f51d30a571fc
6ced62ac-e934-43c8-aa3f-58a36983a3fb
48deab12-032b-412a-9a94-9174ad3effff
0600ece7-7d7f-427e-acb3-3f0cbb4aff7f
3182845c-f678-4c68-9f97-ec9dbac20844
554537ba-20ff-4ae5-8efc-5b4eccb17620
567b491d-86b9-4c32-adfa-a023ced32cad
f7f0b08e-3c5b-420d-be0d-254ba4b7576d
1fa120ee-725b-485b-af9f-789bb2305fd1
f17b30f3-6b23-41eb-a404-fe300498796d
d56395cd-2f89-4be2-8f12-0bf18d0fc5ab
5cc61d5a-558e-4ab3-8b4f-03f5aa6bad03
b9953c84-0d3b-4836-8f25-bae823565470

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: