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)

018f1403-2db9-7b44-bcf3-44b44b71d4b3
018f1403-2db9-7d03-9899-b6656f5f5f7a
018f1403-2db9-7e6f-8f26-841a1b081ea1
018f1403-2db9-7fb3-b02c-380123390cef
018f1403-2dba-70f2-aafe-1ac1033f0e59
018f1403-2dba-7232-ae16-b2c243774a49
018f1403-2dba-7371-8843-2b974a31cead
018f1403-2dba-74b1-9115-6de77c67cf2c
018f1403-2dba-75ec-84a1-2cce51c13c66
018f1403-2dba-772c-8141-e30e5687dc79
018f1403-2dba-786b-9f42-12852bae4c99
018f1403-2dba-79a6-a81d-d60dee1d1d79
018f1403-2dba-7aea-955a-6dbe286df107
018f1403-2dba-7c2e-a0fd-1e9f9b87b1b0
018f1403-2dba-7d71-b577-66ffb89fd6a8

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)

1ef02cfc-fab9-670c-a944-4cf95d479851
1ef02cfc-fab9-695a-a944-4cf95d479851
1ef02cfc-fab9-6ad6-a944-4cf95d479851
1ef02cfc-fab9-6c34-a944-4cf95d479851
1ef02cfc-fab9-6d88-a944-4cf95d479851
1ef02cfc-fab9-6ef0-a944-4cf95d479851
1ef02cfc-faba-6044-a944-4cf95d479851
1ef02cfc-faba-61a2-a944-4cf95d479851
1ef02cfc-faba-62f6-a944-4cf95d479851
1ef02cfc-faba-644a-a944-4cf95d479851
1ef02cfc-faba-663e-a944-4cf95d479851
1ef02cfc-faba-67a6-a944-4cf95d479851
1ef02cfc-faba-68fa-a944-4cf95d479851
1ef02cfc-faba-6a4e-a944-4cf95d479851
1ef02cfc-faba-6b98-a944-4cf95d479851

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)

3e73cd3a-6858-49c3-9dbd-307af0f33a51
03d70b85-195f-417e-9a88-842a6c6feb9c
e04bcf0f-bd8e-499c-a897-e30929544776
bf4eb1c1-f83a-4beb-8e46-e31dc3a0bc39
b8bf4a76-7d31-488d-939f-2f755e562561
2a06b0e3-1687-4a8f-8a34-a08dfbdca305
7b8e06cd-fe07-4c9c-b470-7b191a6835c4
a01a4224-84b0-4449-b7ec-4a622bb61a34
6a22f17e-2863-40e9-a627-3a564f644b05
3f426ed2-0c2f-4d1c-8d7d-9a1f60a104c9
8efdd0cc-a5dc-4760-9e91-f6d864412d65
9cb6b1db-d6ec-4e4f-9369-8450e3af65f1
9f5d09c5-06f6-44a9-9213-772687d29dd4
dc6e2407-9cf2-49d7-9b43-108ccd34e899
5490d5b3-9865-4088-8907-eb5cb6cf2896

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)

cfabb2b4-02cf-11ef-a944-4cf95d479851
cfabb34a-02cf-11ef-a944-4cf95d479851
cfabb3e0-02cf-11ef-a944-4cf95d479851
cfabb480-02cf-11ef-a944-4cf95d479851
cfabb516-02cf-11ef-a944-4cf95d479851
cfabb5ac-02cf-11ef-a944-4cf95d479851
cfabb64c-02cf-11ef-a944-4cf95d479851
cfabb6e2-02cf-11ef-a944-4cf95d479851
cfabb782-02cf-11ef-a944-4cf95d479851
cfabb822-02cf-11ef-a944-4cf95d479851
cfabb8b8-02cf-11ef-a944-4cf95d479851
cfabb958-02cf-11ef-a944-4cf95d479851
cfabb9f8-02cf-11ef-a944-4cf95d479851
cfabba8e-02cf-11ef-a944-4cf95d479851
cfabbb2e-02cf-11ef-a944-4cf95d479851

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)

9715bd17-0199-8074-87e8-5ce32bd83b96
8372be17-0199-8074-87e8-5ce32bd83b96
ac86bf17-0199-8074-87e8-5ce32bd83b96
a0fcc017-0199-8074-87e8-5ce32bd83b96
369bc117-0199-8074-87e8-5ce32bd83b96
6d9ac217-0199-8074-87e8-5ce32bd83b96
f407c317-0199-8074-87e8-5ce32bd83b96
581ac417-0199-8074-87e8-5ce32bd83b96
0966c517-0199-8074-87e8-5ce32bd83b96
8258c617-0199-8074-87e8-5ce32bd83b96
6ba2c717-0199-8074-87e8-5ce32bd83b96
a801c817-0199-8074-87e8-5ce32bd83b96
05d2c917-0199-8074-87e8-5ce32bd83b96
06ddca17-0199-8074-87e8-5ce32bd83b96
3dbdcb17-0199-8074-87e8-5ce32bd83b96

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: