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)

019ac668-6db8-78a0-a42d-cc90e01634ba
019ac668-6db8-7a25-b9c3-ca76c619b833
019ac668-6db8-7b69-b217-614a97538b9f
019ac668-6db8-7c8c-9367-aad68f10d798
019ac668-6db8-7da6-a527-a7370b6c08c3
019ac668-6db8-7ec1-9402-bd06cf7d1de8
019ac668-6db8-7fdc-b04a-6181f448b2c0
019ac668-6db9-70f6-8fc4-754697335f07
019ac668-6db9-7211-969a-3a358822f1be
019ac668-6db9-7330-a195-06faeab95dc0
019ac668-6db9-7446-a856-cde0488282e8
019ac668-6db9-7561-9e7f-85b265fcef2f
019ac668-6db9-767b-be49-a5f9b7ede9ff
019ac668-6db9-7792-a71d-a95671fced6a
019ac668-6db9-78ad-8070-51c6d5c55091

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)

1f0cbb86-2bf6-639a-a8b7-4cf95d479851
1f0cbb86-2bf6-6520-a8b7-4cf95d479851
1f0cbb86-2bf6-6606-a8b7-4cf95d479851
1f0cbb86-2bf6-66d8-a8b7-4cf95d479851
1f0cbb86-2bf6-67a0-a8b7-4cf95d479851
1f0cbb86-2bf6-6868-a8b7-4cf95d479851
1f0cbb86-2bf6-6926-a8b7-4cf95d479851
1f0cbb86-2bf6-69e4-a8b7-4cf95d479851
1f0cbb86-2bf6-6aac-a8b7-4cf95d479851
1f0cbb86-2bf6-6b74-a8b7-4cf95d479851
1f0cbb86-2bf6-6cb4-a8b7-4cf95d479851
1f0cbb86-2bf6-6d86-a8b7-4cf95d479851
1f0cbb86-2bf6-6e4e-a8b7-4cf95d479851
1f0cbb86-2bf6-6f16-a8b7-4cf95d479851
1f0cbb86-2bf6-6fd4-a8b7-4cf95d479851

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)

786ff96a-b2d4-4578-a39e-88f6e438dcf4
5e1797c3-996e-4a44-86be-40b3c1b3c38b
43120155-a3ce-4a85-8cb2-004b3c75388c
977445c5-9c7a-42de-9523-55c5be9b06e1
0b842261-fee1-4169-9c1f-d15538dcfa47
85233964-2237-46d2-afe6-4b7c25177a04
c0d33841-6dda-4044-90bc-17f541919fda
81170a76-d001-4d03-830e-d3aa3313f5ea
71d58786-a82f-4b97-9247-a925c049a998
bd1cba18-50af-4cee-9253-a118647bc1cc
eef2fbe6-c16c-4886-82c6-9b02715543a7
fd208a27-247b-40b7-ae72-6d960bbade31
73845105-1718-4837-b41a-95dcf61797b7
5c49e821-25bf-486e-aa60-db3a2d5b50a7
21a8c0be-bcfd-45a6-b858-bd475c57c722

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)

62bf74e8-cbb8-11f0-a8b7-4cf95d479851
62bf754c-cbb8-11f0-a8b7-4cf95d479851
62bf75ba-cbb8-11f0-a8b7-4cf95d479851
62bf7628-cbb8-11f0-a8b7-4cf95d479851
62bf7696-cbb8-11f0-a8b7-4cf95d479851
62bf7704-cbb8-11f0-a8b7-4cf95d479851
62bf7768-cbb8-11f0-a8b7-4cf95d479851
62bf77cc-cbb8-11f0-a8b7-4cf95d479851
62bf783a-cbb8-11f0-a8b7-4cf95d479851
62bf789e-cbb8-11f0-a8b7-4cf95d479851
62bf7902-cbb8-11f0-a8b7-4cf95d479851
62bf7966-cbb8-11f0-a8b7-4cf95d479851
62bf79c0-cbb8-11f0-a8b7-4cf95d479851
62bf7a24-cbb8-11f0-a8b7-4cf95d479851
62bf7a88-cbb8-11f0-a8b7-4cf95d479851

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)

c6eff603-2704-8b14-87e9-5ce32bd83b97
49aef703-2704-8b14-87e9-5ce32bd83b97
06b0f803-2704-8b14-87e9-5ce32bd83b97
6ec3f903-2704-8b14-87e9-5ce32bd83b97
b185fa03-2704-8b14-87e9-5ce32bd83b97
9646fb03-2704-8b14-87e9-5ce32bd83b97
b10dfc03-2704-8b14-87e9-5ce32bd83b97
796bfd03-2704-8b14-87e9-5ce32bd83b97
31bffe03-2704-8b14-87e9-5ce32bd83b97
6611ff03-2704-8b14-87e9-5ce32bd83b97
f6820104-2704-8b14-87e9-5ce32bd83b97
fe3a0204-2704-8b14-87e9-5ce32bd83b97
4b5c0304-2704-8b14-87e9-5ce32bd83b97
5afa0404-2704-8b14-87e9-5ce32bd83b97
c44c0504-2704-8b14-87e9-5ce32bd83b97

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: