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)

019a8d8a-bc58-744e-b603-416d7cac385f
019a8d8a-bc58-75fc-84cf-876592c6e5b1
019a8d8a-bc58-7748-87f1-f3559cd83fc7
019a8d8a-bc58-7867-b005-9bd365809047
019a8d8a-bc58-798a-a847-84ecbf711226
019a8d8a-bc58-7aad-8446-776b4aeccd43
019a8d8a-bc58-7bc7-890b-cc93d6c4140b
019a8d8a-bc58-7ce6-b706-09431ddf44f6
019a8d8a-bc58-7e00-8686-2c15d5d60c01
019a8d8a-bc58-7f1f-9c18-88638f334fe4
019a8d8a-bc59-7042-b91a-7b1c765ac293
019a8d8a-bc59-7165-8df5-1f4319ec6a60
019a8d8a-bc59-7284-ba02-f3be5e64ffc3
019a8d8a-bc59-73b7-8352-a4113e46ff2b
019a8d8a-bc59-74f6-bacf-ddcaf5a2ffd4

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)

1f0c30b0-edea-66a6-8e1b-4cf95d479851
1f0c30b0-edea-6868-8e1b-4cf95d479851
1f0c30b0-edea-6958-8e1b-4cf95d479851
1f0c30b0-edea-6a2a-8e1b-4cf95d479851
1f0c30b0-edea-6afc-8e1b-4cf95d479851
1f0c30b0-edea-6bc4-8e1b-4cf95d479851
1f0c30b0-edea-6c8c-8e1b-4cf95d479851
1f0c30b0-edea-6d54-8e1b-4cf95d479851
1f0c30b0-edea-6e1c-8e1b-4cf95d479851
1f0c30b0-edea-6ee4-8e1b-4cf95d479851
1f0c30b0-edeb-602e-8e1b-4cf95d479851
1f0c30b0-edeb-6100-8e1b-4cf95d479851
1f0c30b0-edeb-61d2-8e1b-4cf95d479851
1f0c30b0-edeb-629a-8e1b-4cf95d479851
1f0c30b0-edeb-636c-8e1b-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)

84a6f895-5d7a-4cac-920a-1e86bd831c6b
137b5312-247d-455c-b20c-ba727599159e
9c033118-3a6a-4729-9f03-c4434faa9427
ca5b6e96-33cc-48ac-8164-de8e36bc2fdc
17753ed5-f14c-4c5b-817e-fb28d0d2d916
3be5c981-87b0-4a04-b9c1-0332fd9ba876
cde7e6ed-efbb-4da9-b860-467e3ba3c7e7
31c06ca5-31ef-4714-bfb7-385e9ea216b7
2c79c04d-a31a-45a7-a83e-b0b25f9dfc60
de7bdcec-0fc4-4655-8895-e0a8e283da5f
1b79af96-809d-4df6-b3a3-a2183ab815cc
ca06a5f2-8a2a-4da1-b0c5-fcd21f2a3ea4
76fdb48f-31ca-4a16-bafd-7c5f552f68b1
a4c6f3fd-20c6-43a9-8b1c-4fdbc100004e
b1f77a9c-80a5-44e9-af80-3f0a30ebe419

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)

0edeb88a-c30b-11f0-8e1b-4cf95d479851
0edeb8f8-c30b-11f0-8e1b-4cf95d479851
0edeb95c-c30b-11f0-8e1b-4cf95d479851
0edeb9c0-c30b-11f0-8e1b-4cf95d479851
0edeba24-c30b-11f0-8e1b-4cf95d479851
0edeba88-c30b-11f0-8e1b-4cf95d479851
0edebae2-c30b-11f0-8e1b-4cf95d479851
0edebb46-c30b-11f0-8e1b-4cf95d479851
0edebbaa-c30b-11f0-8e1b-4cf95d479851
0edebc18-c30b-11f0-8e1b-4cf95d479851
0edebc7c-c30b-11f0-8e1b-4cf95d479851
0edebce0-c30b-11f0-8e1b-4cf95d479851
0edebd44-c30b-11f0-8e1b-4cf95d479851
0edebda8-c30b-11f0-8e1b-4cf95d479851
0edebe0c-c30b-11f0-8e1b-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)

933d010b-ea03-8014-87e9-5ce32bd83b97
2d31020b-ea03-8014-87e9-5ce32bd83b97
a750030b-ea03-8014-87e9-5ce32bd83b97
8b26040b-ea03-8014-87e9-5ce32bd83b97
8241050b-ea03-8014-87e9-5ce32bd83b97
1299060b-ea03-8014-87e9-5ce32bd83b97
d473070b-ea03-8014-87e9-5ce32bd83b97
a71b080b-ea03-8014-87e9-5ce32bd83b97
3546090b-ea03-8014-87e9-5ce32bd83b97
1a030a0b-ea03-8014-87e9-5ce32bd83b97
89640b0b-ea03-8014-87e9-5ce32bd83b97
e75d0c0b-ea03-8014-87e9-5ce32bd83b97
9bc30d0b-ea03-8014-87e9-5ce32bd83b97
78cd0e0b-ea03-8014-87e9-5ce32bd83b97
b1960f0b-ea03-8014-87e9-5ce32bd83b97

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: