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)

01a07eec-b73c-756d-9d65-35be6d7cebbb
01a07eec-b73c-7775-b789-73f64244d5a0
01a07eec-b73c-78ad-a854-c8fc8e821177
01a07eec-b73c-79c7-849d-dddd81de57c7
01a07eec-b73c-7ade-aefa-bb7864959bd1
01a07eec-b73c-7bf0-b05c-ac044e0172fe
01a07eec-b73c-7d0f-b10d-e381f4c9ede3
01a07eec-b73c-7e21-b683-1e5978170fcf
01a07eec-b73c-7f34-a925-41beedd865b8
01a07eec-b73d-7046-9e43-20cd91a6df21
01a07eec-b73d-715d-98f4-95e58acbe637
01a07eec-b73d-726f-81a5-29e50b8911e1
01a07eec-b73d-7386-bfae-c2d6ac6bb2e8
01a07eec-b73d-74bd-a084-b78a42d5c441
01a07eec-b73d-75cf-958c-3c350a56b5fe

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)

1f1ab301-2371-60c8-ac48-4cf95d479851
1f1ab301-2371-6262-ac48-4cf95d479851
1f1ab301-2371-633e-ac48-4cf95d479851
1f1ab301-2371-6410-ac48-4cf95d479851
1f1ab301-2371-64ce-ac48-4cf95d479851
1f1ab301-2371-658c-ac48-4cf95d479851
1f1ab301-2371-664a-ac48-4cf95d479851
1f1ab301-2371-6708-ac48-4cf95d479851
1f1ab301-2371-67c6-ac48-4cf95d479851
1f1ab301-2371-6884-ac48-4cf95d479851
1f1ab301-2371-69e2-ac48-4cf95d479851
1f1ab301-2371-6aaa-ac48-4cf95d479851
1f1ab301-2371-6b68-ac48-4cf95d479851
1f1ab301-2371-6c26-ac48-4cf95d479851
1f1ab301-2371-6cda-ac48-4cf95d479851

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)

12371dac-ab30-11f1-ac48-4cf95d479851
12371e10-ab30-11f1-ac48-4cf95d479851
12371e74-ab30-11f1-ac48-4cf95d479851
12371ed8-ab30-11f1-ac48-4cf95d479851
12371f46-ab30-11f1-ac48-4cf95d479851
12371fb4-ab30-11f1-ac48-4cf95d479851
12372018-ab30-11f1-ac48-4cf95d479851
12372086-ab30-11f1-ac48-4cf95d479851
123720e0-ab30-11f1-ac48-4cf95d479851
12372144-ab30-11f1-ac48-4cf95d479851
123721a8-ab30-11f1-ac48-4cf95d479851
1237220c-ab30-11f1-ac48-4cf95d479851
12372266-ab30-11f1-ac48-4cf95d479851
123722c0-ab30-11f1-ac48-4cf95d479851
1237232e-ab30-11f1-ac48-4cf95d479851

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)

699fc125-ab00-8b0f-87ea-5ce32bd83b97
76f8c325-ab00-8b0f-87ea-5ce32bd83b97
61bac425-ab00-8b0f-87ea-5ce32bd83b97
21d5c525-ab00-8b0f-87ea-5ce32bd83b97
1f01c625-ab00-8b0f-87ea-5ce32bd83b97
e010c725-ab00-8b0f-87ea-5ce32bd83b97
8fa2c825-ab00-8b0f-87ea-5ce32bd83b97
33aec925-ab00-8b0f-87ea-5ce32bd83b97
c005ca25-ab00-8b0f-87ea-5ce32bd83b97
ffb4cb25-ab00-8b0f-87ea-5ce32bd83b97
669ccc25-ab00-8b0f-87ea-5ce32bd83b97
c684cd25-ab00-8b0f-87ea-5ce32bd83b97
3784ce25-ab00-8b0f-87ea-5ce32bd83b97
25facf25-ab00-8b0f-87ea-5ce32bd83b97
f933d025-ab00-8b0f-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)

e8103870-ddc1-475f-b6b0-d21d036fa69b
17511dd8-1839-4044-97f2-d96bf46e3c11
c2762b8f-875d-4ea1-8e1a-74172c1520d3
9b3ec3d9-6499-4e16-9fc4-0fc0647e1927
9555b43c-8695-4a17-ac2f-774e39094103
fd2f886d-3ea7-42dd-abd3-044dfc4102a8
61a2d1b6-dac9-4620-8322-c8307318064b
4c6b230f-4ed7-4b7f-9542-8beea8f624c6
a43ec667-0289-4af2-ab44-7c303ba23c63
82f6c034-6b2a-4c36-9159-b2182e1add0c
8f23108c-6634-48af-802e-7f89ce3da015
0857e3c6-e7e9-4b1b-b3fe-a91539b4c4e0
f3ec7dd3-3e14-4cc9-b710-36a39c69dc8d
ba1b70e6-186b-4b60-8c89-9e48a5491b3d
e61b7f63-944e-462a-b774-568f13e88399

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: