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)

019724d9-62dc-75f8-a47b-a17c95e74865
019724d9-62dc-779e-995c-94dfd3b6048b
019724d9-62dc-78e6-b248-19326ea8eb47
019724d9-62dc-7a09-8728-da7373343d4d
019724d9-62dc-7b23-9ebd-d4632629f3ad
019724d9-62dc-7c3e-a14c-2f8e27be3149
019724d9-62dc-7d5d-b068-a0b0d9559022
019724d9-62dc-7e7b-a945-f0195006d03f
019724d9-62dc-7f96-849b-c6a5bb0525df
019724d9-62dd-70b5-b3c5-c9ad2c5e86de
019724d9-62dd-71cf-a739-353419303fb0
019724d9-62dd-72ee-b6b0-6586ef0b95e7
019724d9-62dd-7409-ad2a-1f358c259efa
019724d9-62dd-7527-930e-a505ba8458ad
019724d9-62dd-7642-afda-5bb8574dc908

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)

1f03de17-f272-6be0-8d1e-4cf95d479851
1f03de17-f272-6d7a-8d1e-4cf95d479851
1f03de17-f272-6e60-8d1e-4cf95d479851
1f03de17-f272-6f28-8d1e-4cf95d479851
1f03de17-f272-6ff0-8d1e-4cf95d479851
1f03de17-f273-60b8-8d1e-4cf95d479851
1f03de17-f273-6176-8d1e-4cf95d479851
1f03de17-f273-623e-8d1e-4cf95d479851
1f03de17-f273-6306-8d1e-4cf95d479851
1f03de17-f273-63c4-8d1e-4cf95d479851
1f03de17-f273-6554-8d1e-4cf95d479851
1f03de17-f273-66d0-8d1e-4cf95d479851
1f03de17-f273-67ca-8d1e-4cf95d479851
1f03de17-f273-6892-8d1e-4cf95d479851
1f03de17-f273-6946-8d1e-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)

e24fc617-5af5-4d8b-8ffd-0f8a5880755f
0e1bf1e4-374c-4c72-8156-7301bfa631d6
f5652900-98b0-408c-9dd3-e084b26aa534
e94e482a-65de-4e8e-ad40-f3c244eb3571
ea7e6573-c3ab-48c8-be8a-53c16b02d7d7
cb31fa09-b278-4970-aa21-dd4a2ae68b2c
ed693968-e8a5-4523-8255-7c57f9dfc920
ca505abe-b068-430b-ac1d-996f6d85e0fb
586b9128-72ae-4940-84e3-3ccb28035b10
2c0f0a0b-f285-4fa8-8ef3-e4614dd5d129
a08685d8-f2ec-4522-b617-c0ca58ba9b37
ba88a520-680f-4106-ae54-32960236f76a
b860fa90-ad8c-405d-9a3f-63450c99c07f
bb9e42b6-f82e-4c93-ba04-51c65d093422
cab1fcbf-f2bc-443d-b1bc-4c6eb886a2cc

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)

7f273f40-3de1-11f0-8d1e-4cf95d479851
7f273fa4-3de1-11f0-8d1e-4cf95d479851
7f274008-3de1-11f0-8d1e-4cf95d479851
7f274062-3de1-11f0-8d1e-4cf95d479851
7f2740bc-3de1-11f0-8d1e-4cf95d479851
7f274120-3de1-11f0-8d1e-4cf95d479851
7f27417a-3de1-11f0-8d1e-4cf95d479851
7f2741de-3de1-11f0-8d1e-4cf95d479851
7f274238-3de1-11f0-8d1e-4cf95d479851
7f274292-3de1-11f0-8d1e-4cf95d479851
7f2742f6-3de1-11f0-8d1e-4cf95d479851
7f27435a-3de1-11f0-8d1e-4cf95d479851
7f2743b4-3de1-11f0-8d1e-4cf95d479851
7f274418-3de1-11f0-8d1e-4cf95d479851
7f27447c-3de1-11f0-8d1e-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

c077de23-0153-8097-87e9-5ce32bd83b96
a28fdf23-0153-8097-87e9-5ce32bd83b96
8291e023-0153-8097-87e9-5ce32bd83b96
3db7e123-0153-8097-87e9-5ce32bd83b96
0297e223-0153-8097-87e9-5ce32bd83b96
65e6e323-0153-8097-87e9-5ce32bd83b96
0651e423-0153-8097-87e9-5ce32bd83b96
50e9e523-0153-8097-87e9-5ce32bd83b96
a970e623-0153-8097-87e9-5ce32bd83b96
3038e723-0153-8097-87e9-5ce32bd83b96
f199e923-0153-8097-87e9-5ce32bd83b96
a457ea23-0153-8097-87e9-5ce32bd83b96
fe6feb23-0153-8097-87e9-5ce32bd83b96
57bfec23-0153-8097-87e9-5ce32bd83b96
f03fed23-0153-8097-87e9-5ce32bd83b96

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: