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)

0198bdc8-4650-723e-a856-273bf0a7fa4b
0198bdc8-4650-73bf-82e9-8d9eb36a5344
0198bdc8-4650-74fe-846c-e1c8f5e17109
0198bdc8-4650-7621-b05a-69609cfdf3b0
0198bdc8-4650-7761-a4ec-b0b94f908757
0198bdc8-4650-78c1-884f-94dbe7e7df18
0198bdc8-4650-7a15-8315-f1e32775046f
0198bdc8-4650-7b5d-8353-1d88c170e916
0198bdc8-4650-7ca4-8e61-7c8e42ca0455
0198bdc8-4650-7de4-bd54-119b72c1a94a
0198bdc8-4650-7f2c-a453-183c7f43cb02
0198bdc8-4651-706b-9fc0-1648744a9705
0198bdc8-4651-71b3-a894-425615f4a1ad
0198bdc8-4651-72f2-984d-656a2f425bd2
0198bdc8-4651-7432-932e-ffc3407d9878

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)

1f07c477-2bc0-6b24-94ba-4cf95d479851
1f07c477-2bc0-6d68-94ba-4cf95d479851
1f07c477-2bc0-6ee4-94ba-4cf95d479851
1f07c477-2bc1-604c-94ba-4cf95d479851
1f07c477-2bc1-61aa-94ba-4cf95d479851
1f07c477-2bc1-62fe-94ba-4cf95d479851
1f07c477-2bc1-643e-94ba-4cf95d479851
1f07c477-2bc1-6588-94ba-4cf95d479851
1f07c477-2bc1-66d2-94ba-4cf95d479851
1f07c477-2bc1-6812-94ba-4cf95d479851
1f07c477-2bc1-6a10-94ba-4cf95d479851
1f07c477-2bc1-6b6e-94ba-4cf95d479851
1f07c477-2bc1-6cae-94ba-4cf95d479851
1f07c477-2bc1-6df8-94ba-4cf95d479851
1f07c477-2bc1-6f38-94ba-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)

88eb44d1-e223-4d3f-b7b5-b9f58763794a
669eb638-531f-4eb9-9097-7de2f01aea8b
3973c4cc-8209-484e-8019-08ff5bb2d090
e4e3e6ca-ada7-454b-a087-82b14b6d600b
47669768-b9b5-4943-8582-9a6ca0dece79
b7e2a49e-1120-4ac5-8a64-73027ddd193a
0f8009cd-12f2-4c91-b80a-61941917bd2d
0d369398-5c19-4704-a1c9-cb7f1c452154
535633d0-8394-47d3-9622-e732b7ceb0b0
8fb815a3-4de4-4ec9-be73-a01e607f7fe2
94fe50b4-e9f7-4194-a47d-011221a579ad
53bc349c-87ce-46e4-ad15-d08a91639080
0135d404-5c7c-43f7-adec-0d2454c3edb3
ff540e1e-bc47-4131-bab3-4e22993353ab
649bd86c-1075-4527-a8ef-2b6e7123446f

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)

72bc2668-7c47-11f0-94ba-4cf95d479851
72bc2794-7c47-11f0-94ba-4cf95d479851
72bc282a-7c47-11f0-94ba-4cf95d479851
72bc28b6-7c47-11f0-94ba-4cf95d479851
72bc294c-7c47-11f0-94ba-4cf95d479851
72bc29e2-7c47-11f0-94ba-4cf95d479851
72bc2a78-7c47-11f0-94ba-4cf95d479851
72bc2b0e-7c47-11f0-94ba-4cf95d479851
72bc2ba4-7c47-11f0-94ba-4cf95d479851
72bc2c30-7c47-11f0-94ba-4cf95d479851
72bc2cbc-7c47-11f0-94ba-4cf95d479851
72bc2d52-7c47-11f0-94ba-4cf95d479851
72bc2de8-7c47-11f0-94ba-4cf95d479851
72bc2e74-7c47-11f0-94ba-4cf95d479851
72bc2f00-7c47-11f0-94ba-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)

cd7ccb23-9d03-860e-87e9-5ce32bd83b97
eaeacc23-9d03-860e-87e9-5ce32bd83b97
53f1cd23-9d03-860e-87e9-5ce32bd83b97
ef6ace23-9d03-860e-87e9-5ce32bd83b97
d042cf23-9d03-860e-87e9-5ce32bd83b97
a535d023-9d03-860e-87e9-5ce32bd83b97
4380d123-9d03-860e-87e9-5ce32bd83b97
f6f0d223-9d03-860e-87e9-5ce32bd83b97
2fabd323-9d03-860e-87e9-5ce32bd83b97
210ed423-9d03-860e-87e9-5ce32bd83b97
d97cd523-9d03-860e-87e9-5ce32bd83b97
8263d623-9d03-860e-87e9-5ce32bd83b97
7652d723-9d03-860e-87e9-5ce32bd83b97
cf25d823-9d03-860e-87e9-5ce32bd83b97
cb08d923-9d03-860e-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: