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)

01995411-dee7-78da-bfc9-0ecd9646c665
01995411-dee7-7a6b-b2b7-d5ee3d7c6c3f
01995411-dee7-7baf-91f3-189b9b5c64fd
01995411-dee7-7cda-a0d1-0a96620d98d3
01995411-dee7-7df8-82a6-63479274d4b0
01995411-dee7-7f17-9eca-757a1ab2475d
01995411-dee8-7036-81af-cf0fb2137daf
01995411-dee8-7154-be0b-88356dd96cb0
01995411-dee8-726f-9f39-5ca4e2532802
01995411-dee8-738e-a56f-e4d6e8d92074
01995411-dee8-74a8-abb8-9f37fe3a58e1
01995411-dee8-75e8-b7d4-b7c19e8616ba
01995411-dee8-7769-bfda-80e60b65d260
01995411-dee8-78c1-8ae6-ec3c671c994f
01995411-dee8-79e8-a8b5-1b37d39f090d

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)

1f093360-d94a-62e6-b273-4cf95d479851
1f093360-d94a-64a8-b273-4cf95d479851
1f093360-d94a-658e-b273-4cf95d479851
1f093360-d94a-666a-b273-4cf95d479851
1f093360-d94a-6732-b273-4cf95d479851
1f093360-d94a-67fa-b273-4cf95d479851
1f093360-d94a-68b8-b273-4cf95d479851
1f093360-d94a-6976-b273-4cf95d479851
1f093360-d94a-6a3e-b273-4cf95d479851
1f093360-d94a-6afc-b273-4cf95d479851
1f093360-d94a-6c50-b273-4cf95d479851
1f093360-d94a-6d18-b273-4cf95d479851
1f093360-d94a-6dd6-b273-4cf95d479851
1f093360-d94a-6e9e-b273-4cf95d479851
1f093360-d94a-6f5c-b273-4cf95d479851

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)

2ce0a3f9-cbf2-455b-8b07-be7b53e0744c
ef030fe4-5365-4821-8a13-8eea3f969ebb
e31a596c-35b3-44d4-8009-c933e7a86350
7d58b05d-4fb2-42d4-9e41-29897008d98c
e44931b6-7e25-488a-9252-aa8cc6cb0e7e
e5f7c51a-6480-47e5-a542-dfcb0eb3dd99
dc7115e1-8a35-4ec0-9b15-c4b728c8161a
876cc46b-e9a6-40be-aa71-1ecf171e7086
b45a1474-4784-4cb7-ad83-59156dd88f2e
83afa626-ef6a-4319-8d69-c3ad71363a78
316f4ce1-cc1f-4856-9b54-56f21a67dfc3
a88592b0-3205-476b-8bbe-a7cf7ddb7da6
bdd347fd-d2a4-4fe9-a04a-2aa334179150
2c5dfb5e-f1f6-4c94-aeb7-a08887be4bca
296572f0-b8f9-4b11-a34e-93e90865be71

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)

0d94b48e-9336-11f0-b273-4cf95d479851
0d94b4f2-9336-11f0-b273-4cf95d479851
0d94b556-9336-11f0-b273-4cf95d479851
0d94b5ba-9336-11f0-b273-4cf95d479851
0d94b614-9336-11f0-b273-4cf95d479851
0d94b66e-9336-11f0-b273-4cf95d479851
0d94b6d2-9336-11f0-b273-4cf95d479851
0d94b736-9336-11f0-b273-4cf95d479851
0d94b79a-9336-11f0-b273-4cf95d479851
0d94b812-9336-11f0-b273-4cf95d479851
0d94b876-9336-11f0-b273-4cf95d479851
0d94b8da-9336-11f0-b273-4cf95d479851
0d94b948-9336-11f0-b273-4cf95d479851
0d94b9ac-9336-11f0-b273-4cf95d479851
0d94ba06-9336-11f0-b273-4cf95d479851

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)

04676201-a504-8310-87e9-5ce32bd83b97
27cc6301-a504-8310-87e9-5ce32bd83b97
de7b6401-a504-8310-87e9-5ce32bd83b97
df686501-a504-8310-87e9-5ce32bd83b97
d5df6601-a504-8310-87e9-5ce32bd83b97
ebd56701-a504-8310-87e9-5ce32bd83b97
c6dc6901-a504-8310-87e9-5ce32bd83b97
7b016a01-a504-8310-87e9-5ce32bd83b97
f8ce6b01-a504-8310-87e9-5ce32bd83b97
5b806c01-a504-8310-87e9-5ce32bd83b97
e77a6d01-a504-8310-87e9-5ce32bd83b97
4c8c6e01-a504-8310-87e9-5ce32bd83b97
64366f01-a504-8310-87e9-5ce32bd83b97
fad67001-a504-8310-87e9-5ce32bd83b97
f6ae7101-a504-8310-87e9-5ce32bd83b97

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: