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)

019db39c-552b-7faf-8fb8-f15798dee658
019db39c-552c-715d-a932-8b8aaacf6e33
019db39c-552c-72b5-983b-722f2d6ac164
019db39c-552c-73d8-a281-b5fd21a0d949
019db39c-552c-74f2-a238-bb371490aaec
019db39c-552c-760d-9cc1-66c6548032d7
019db39c-552c-7723-9639-dff8005d2b30
019db39c-552c-783a-9627-ef74715c6817
019db39c-552c-7954-8a08-c7372c1cf688
019db39c-552c-7a6b-9694-3ec603dc0e74
019db39c-552c-7b82-b0fb-50c26c150565
019db39c-552c-7c9c-8b71-22c05d903945
019db39c-552c-7db3-a00f-8e2fc6c9c237
019db39c-552c-7ecd-8ad8-58f8f678563a
019db39c-552c-7fe4-b1b0-e02625fd07c8

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)

1f13e0a1-e407-61ae-8fea-4cf95d479851
1f13e0a1-e407-635c-8fea-4cf95d479851
1f13e0a1-e407-644c-8fea-4cf95d479851
1f13e0a1-e407-6514-8fea-4cf95d479851
1f13e0a1-e407-65dc-8fea-4cf95d479851
1f13e0a1-e407-669a-8fea-4cf95d479851
1f13e0a1-e407-6762-8fea-4cf95d479851
1f13e0a1-e407-6820-8fea-4cf95d479851
1f13e0a1-e407-68e8-8fea-4cf95d479851
1f13e0a1-e407-699c-8fea-4cf95d479851
1f13e0a1-e407-6ae6-8fea-4cf95d479851
1f13e0a1-e407-6bae-8fea-4cf95d479851
1f13e0a1-e407-6c62-8fea-4cf95d479851
1f13e0a1-e407-6d20-8fea-4cf95d479851
1f13e0a1-e407-6dde-8fea-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)

662e570b-a1d8-4cd0-b992-87e5aac349a1
d59676ad-da87-46c4-bbaf-e8bd6781c096
6d3bd1cd-ebdf-4a1d-bf31-83cbf9795187
f8792a78-2fda-4133-b7b9-94ac7e90947a
7cdadfac-4603-4684-977a-11e0a814e970
fb66670d-38ba-4bae-8669-5231fe253fef
e96f98ba-00ed-4f27-80d8-93e1bf5652f8
4003e2c3-1382-4284-87ca-c58da995a7d7
dbabf882-cdbc-4fdc-9eff-9caf05f52efd
c04b8793-280a-4fbb-9029-f61ed4539135
aa5ac9f3-b643-479b-8379-327ea2be585d
b9dfa831-f89e-4f97-8d60-3a5af69da3ea
1f1dee23-4a69-412d-8ff1-c4bf839868be
1b5ba347-4371-42c9-b3f7-ad7fe6ce0cae
e7a3cc1e-ffa4-4ee0-afd5-4c0e11bc6908

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)

1e4082fc-3e0a-11f1-8fea-4cf95d479851
1e408360-3e0a-11f1-8fea-4cf95d479851
1e4083c4-3e0a-11f1-8fea-4cf95d479851
1e40841e-3e0a-11f1-8fea-4cf95d479851
1e408482-3e0a-11f1-8fea-4cf95d479851
1e4084dc-3e0a-11f1-8fea-4cf95d479851
1e408540-3e0a-11f1-8fea-4cf95d479851
1e4085a4-3e0a-11f1-8fea-4cf95d479851
1e4085fe-3e0a-11f1-8fea-4cf95d479851
1e408658-3e0a-11f1-8fea-4cf95d479851
1e4086bc-3e0a-11f1-8fea-4cf95d479851
1e408716-3e0a-11f1-8fea-4cf95d479851
1e408770-3e0a-11f1-8fea-4cf95d479851
1e4087d4-3e0a-11f1-8fea-4cf95d479851
1e408838-3e0a-11f1-8fea-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)

a2cd5514-3b01-8007-87ea-5ce32bd83b97
90845614-3b01-8007-87ea-5ce32bd83b97
3f5d5714-3b01-8007-87ea-5ce32bd83b97
db845814-3b01-8007-87ea-5ce32bd83b97
9baa5914-3b01-8007-87ea-5ce32bd83b97
6e2a5a14-3b01-8007-87ea-5ce32bd83b97
b2865b14-3b01-8007-87ea-5ce32bd83b97
c5a05c14-3b01-8007-87ea-5ce32bd83b97
19ee5d14-3b01-8007-87ea-5ce32bd83b97
186d5e14-3b01-8007-87ea-5ce32bd83b97
53f15f14-3b01-8007-87ea-5ce32bd83b97
dcb56014-3b01-8007-87ea-5ce32bd83b97
ebb26214-3b01-8007-87ea-5ce32bd83b97
8acc6314-3b01-8007-87ea-5ce32bd83b97
fb266414-3b01-8007-87ea-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: