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)

019b999a-2f0b-742e-ac33-817be1709bec
019b999a-2f0b-75c7-8a9c-2330f577ef48
019b999a-2f0b-7703-b553-9acb179d0872
019b999a-2f0b-7825-9c8e-d2761ec4fcd2
019b999a-2f0b-7944-970b-19c6fb43c4d8
019b999a-2f0b-7a5b-967f-51e95ff21906
019b999a-2f0b-7b79-9e8d-4c466e943b50
019b999a-2f0b-7c90-8a04-7b7ec871a60b
019b999a-2f0b-7daa-9c85-e0434631aba5
019b999a-2f0b-7ec5-942e-ee8280bbdabb
019b999a-2f0b-7fe4-930c-a9297e02785b
019b999a-2f0c-70fe-8a7e-c00c60a16211
019b999a-2f0c-7215-bcb6-6195cd7488f2
019b999a-2f0c-7330-bd61-fa4c5d5e4284
019b999a-2f0c-744a-89b3-3cbb83391204

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)

1f0ebf22-a4f1-6334-9aff-4cf95d479851
1f0ebf22-a4f1-64ce-9aff-4cf95d479851
1f0ebf22-a4f1-65aa-9aff-4cf95d479851
1f0ebf22-a4f1-667c-9aff-4cf95d479851
1f0ebf22-a4f1-6744-9aff-4cf95d479851
1f0ebf22-a4f1-6802-9aff-4cf95d479851
1f0ebf22-a4f1-68c0-9aff-4cf95d479851
1f0ebf22-a4f1-6988-9aff-4cf95d479851
1f0ebf22-a4f1-6a46-9aff-4cf95d479851
1f0ebf22-a4f1-6b0e-9aff-4cf95d479851
1f0ebf22-a4f1-6c58-9aff-4cf95d479851
1f0ebf22-a4f1-6dc0-9aff-4cf95d479851
1f0ebf22-a4f1-6eb0-9aff-4cf95d479851
1f0ebf22-a4f1-6f6e-9aff-4cf95d479851
1f0ebf22-a4f2-6022-9aff-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)

c9a3aad5-e5e6-4eba-8535-2477aaa02464
6f1fa620-239a-48f5-b4cd-ae7d7baa0552
0127a791-0c61-4d9b-b88c-5196d36acccd
ae8caeba-c541-47a1-a902-904f3ad86769
0443d258-462b-411f-982c-8a349c3c7dd5
17ed8646-ade9-4110-abd2-b4712a3cc765
ed564662-5e8e-4e5f-8ffb-a40945e8b58e
f9fb706f-f9ad-4734-8981-ff7edac76342
85bb2b0b-e00a-46f1-9e05-448373cb29fe
95a9bb18-0d05-47ab-884b-0b36cc51ff12
33a2b625-34a7-4e33-8cf2-9959264830ac
0ce4711e-656c-4617-8b99-12e1a7598382
0681e1f0-9b97-479b-85eb-efe7a56ef4b8
8a20848b-3cd1-4623-a950-d6424f3641f3
e8d57a8a-4a0f-4ad2-984a-11e2d7a9bdfc

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)

2a4f2554-ebf2-11f0-9aff-4cf95d479851
2a4f25b8-ebf2-11f0-9aff-4cf95d479851
2a4f2626-ebf2-11f0-9aff-4cf95d479851
2a4f268a-ebf2-11f0-9aff-4cf95d479851
2a4f26ee-ebf2-11f0-9aff-4cf95d479851
2a4f2752-ebf2-11f0-9aff-4cf95d479851
2a4f27b6-ebf2-11f0-9aff-4cf95d479851
2a4f2810-ebf2-11f0-9aff-4cf95d479851
2a4f2874-ebf2-11f0-9aff-4cf95d479851
2a4f28d8-ebf2-11f0-9aff-4cf95d479851
2a4f293c-ebf2-11f0-9aff-4cf95d479851
2a4f29a0-ebf2-11f0-9aff-4cf95d479851
2a4f2a04-ebf2-11f0-9aff-4cf95d479851
2a4f2a68-ebf2-11f0-9aff-4cf95d479851
2a4f2ac2-ebf2-11f0-9aff-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)

bf5e4b11-3504-8700-87ea-5ce32bd83b97
42b94c11-3504-8700-87ea-5ce32bd83b97
2d604d11-3504-8700-87ea-5ce32bd83b97
96544e11-3504-8700-87ea-5ce32bd83b97
d3184f11-3504-8700-87ea-5ce32bd83b97
09a45011-3504-8700-87ea-5ce32bd83b97
6a795111-3504-8700-87ea-5ce32bd83b97
4aee5211-3504-8700-87ea-5ce32bd83b97
80b35311-3504-8700-87ea-5ce32bd83b97
015d5411-3504-8700-87ea-5ce32bd83b97
71985511-3504-8700-87ea-5ce32bd83b97
14a45611-3504-8700-87ea-5ce32bd83b97
75f75711-3504-8700-87ea-5ce32bd83b97
621e5811-3504-8700-87ea-5ce32bd83b97
7d795911-3504-8700-87ea-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: