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)

01a0a9fd-a1c4-73e8-9a4f-765eeb6249c4
01a0a9fd-a1c4-75cf-8fe8-e27da8dfb014
01a0a9fd-a1c4-771b-ab13-6db8a13a192b
01a0a9fd-a1c4-7842-881a-4f5c4751f505
01a0a9fd-a1c4-7961-8a23-8bdb06eee2b3
01a0a9fd-a1c4-7a7b-957d-cb9f9f49b864
01a0a9fd-a1c4-7b9a-96ac-c1dd8dc26747
01a0a9fd-a1c4-7cb5-9088-993a80e07822
01a0a9fd-a1c4-7dd3-8ed5-e4b95c2fe1f9
01a0a9fd-a1c4-7ef2-a505-c0f9b0374268
01a0a9fd-a1c5-7011-ab12-06d53adcb439
01a0a9fd-a1c5-7130-ad3a-078e468f9876
01a0a9fd-a1c5-724a-ac81-db504d1a378e
01a0a9fd-a1c5-7365-b8a4-a2e54368b2b2
01a0a9fd-a1c5-73e0-b002-279b9e4dde80

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)

1f1b1c25-7006-6d4c-9938-4cf95d479851
1f1b1c25-7006-6f22-9938-4cf95d479851
1f1b1c25-7007-6008-9938-4cf95d479851
1f1b1c25-7007-60da-9938-4cf95d479851
1f1b1c25-7007-61a2-9938-4cf95d479851
1f1b1c25-7007-6260-9938-4cf95d479851
1f1b1c25-7007-6328-9938-4cf95d479851
1f1b1c25-7007-63e6-9938-4cf95d479851
1f1b1c25-7007-64b8-9938-4cf95d479851
1f1b1c25-7007-6580-9938-4cf95d479851
1f1b1c25-7007-66de-9938-4cf95d479851
1f1b1c25-7007-67b0-9938-4cf95d479851
1f1b1c25-7007-6878-9938-4cf95d479851
1f1b1c25-7007-6940-9938-4cf95d479851
1f1b1c25-7007-69fe-9938-4cf95d479851

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)

57007ada-b1c2-11f1-9938-4cf95d479851
57007b3e-b1c2-11f1-9938-4cf95d479851
57007ba2-b1c2-11f1-9938-4cf95d479851
57007c06-b1c2-11f1-9938-4cf95d479851
57007c6a-b1c2-11f1-9938-4cf95d479851
57007cc4-b1c2-11f1-9938-4cf95d479851
57007d1e-b1c2-11f1-9938-4cf95d479851
57007d82-b1c2-11f1-9938-4cf95d479851
57007ddc-b1c2-11f1-9938-4cf95d479851
57007e36-b1c2-11f1-9938-4cf95d479851
57007e90-b1c2-11f1-9938-4cf95d479851
57007ee0-b1c2-11f1-9938-4cf95d479851
57007f3a-b1c2-11f1-9938-4cf95d479851
57007f94-b1c2-11f1-9938-4cf95d479851
57007ff8-b1c2-11f1-9938-4cf95d479851

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)

4b06a92e-b502-8310-87ea-5ce32bd83b97
95f8aa2e-b502-8310-87ea-5ce32bd83b97
1d08ab2e-b502-8310-87ea-5ce32bd83b97
bacbac2e-b502-8310-87ea-5ce32bd83b97
7bb0ad2e-b502-8310-87ea-5ce32bd83b97
7399ae2e-b502-8310-87ea-5ce32bd83b97
58a2af2e-b502-8310-87ea-5ce32bd83b97
b181b02e-b502-8310-87ea-5ce32bd83b97
e457b12e-b502-8310-87ea-5ce32bd83b97
065cb22e-b502-8310-87ea-5ce32bd83b97
2ec6b32e-b502-8310-87ea-5ce32bd83b97
302db42e-b502-8310-87ea-5ce32bd83b97
289ab52e-b502-8310-87ea-5ce32bd83b97
179eb62e-b502-8310-87ea-5ce32bd83b97
03e0b72e-b502-8310-87ea-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)

b3ac45f3-453e-4d4d-a761-d8ab205d08fe
0cc90a7a-b8a4-433d-98dc-70a5890fc15e
fe469f1c-855c-4fc2-b58f-74ef1f3811e3
db38dd0d-818e-4deb-a0e5-9412c572e113
701a3126-b038-4a3a-89ba-ec3079d8e6cd
94534f93-671f-442b-bb20-6011b6596f81
78bec2d2-2dd1-41f8-b748-909c9af6de8c
115d0931-f1c4-4b33-91b2-24d86be8c41b
b5badc7a-7b72-4036-93f4-2c6d8ae09b2b
ec67f987-c20b-4944-af00-8fe73ee564cd
7697ae85-5ddd-4dcf-a4e7-1658f69ffd97
070bf117-f2bc-44d7-a640-1fb87ecf8770
0deec12d-891c-4aae-989c-2949cd9afc3b
44bd30f2-6396-4bcf-a500-238303f92813
50e3c7cb-3a1a-42d6-9d4f-8e25bd0b18b2

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: