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)

018f89fd-c563-7f54-9c53-78311b1c16b4
018f89fd-c564-70ee-ac39-1f25161fe384
018f89fd-c564-722e-8919-9416e73ab490
018f89fd-c564-7350-85bc-a6e8ab4933b5
018f89fd-c564-746b-bc50-e7383cbd6f82
018f89fd-c564-758e-a089-0c31fbd46b4d
018f89fd-c564-76a8-82ae-d841013002e1
018f89fd-c564-77c7-a42a-db0ede6bfde4
018f89fd-c564-78e2-a50a-287c0990e5cd
018f89fd-c564-79fc-aa1c-c435279d1e2f
018f89fd-c564-7b13-8719-cab66636c1e5
018f89fd-c564-7c2e-aa8c-6626ed57e632
018f89fd-c564-7d4c-87e6-5fffb400f7bf
018f89fd-c564-7e67-a946-abcfaa7e62d0
018f89fd-c564-7f86-aa74-55d44d0ee1f1

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)

1ef14d05-c6ff-6c3e-956c-4cf95d479851
1ef14d05-c6ff-6e6e-956c-4cf95d479851
1ef14d05-c6ff-6fb8-956c-4cf95d479851
1ef14d05-c700-60ee-956c-4cf95d479851
1ef14d05-c700-61ca-956c-4cf95d479851
1ef14d05-c700-6288-956c-4cf95d479851
1ef14d05-c700-6350-956c-4cf95d479851
1ef14d05-c700-640e-956c-4cf95d479851
1ef14d05-c700-64d6-956c-4cf95d479851
1ef14d05-c700-659e-956c-4cf95d479851
1ef14d05-c700-66fc-956c-4cf95d479851
1ef14d05-c700-67c4-956c-4cf95d479851
1ef14d05-c700-6882-956c-4cf95d479851
1ef14d05-c700-6940-956c-4cf95d479851
1ef14d05-c700-69fe-956c-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)

88a6577e-cbb4-4099-a845-a4fac7cb68f0
81f77f55-5b10-4089-9265-f2821a4520c8
67865821-6296-4f08-a039-06171576b7ee
21d45c1d-5b1a-485d-8804-96aae8047e1e
8ee87949-1f99-4d47-b1d3-932091982bb5
a0ebe003-a9b6-4171-828c-ab082d8daa38
e667b113-8bde-4d30-ab9b-dcae56b96b58
7c79a535-7b49-415b-8fca-4e836b6383ba
1733b188-65ba-402f-abaf-dbd370dc62c3
828f611f-571d-416a-bc54-375e05240d06
6191e4c2-7cd2-49a9-a0a4-8f3a226dba07
48151f1d-193a-49ed-a388-06e93db6471f
b33984be-438b-416a-9fc9-cb8f5fd90ec2
cf928403-5c50-4dfe-8a7b-4a479d2929aa
6bccb315-0091-4af6-9c6e-49bdf62d1db9

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)

5c700f44-14d0-11ef-956c-4cf95d479851
5c700fa8-14d0-11ef-956c-4cf95d479851
5c70100c-14d0-11ef-956c-4cf95d479851
5c70107a-14d0-11ef-956c-4cf95d479851
5c7010d4-14d0-11ef-956c-4cf95d479851
5c701138-14d0-11ef-956c-4cf95d479851
5c70119c-14d0-11ef-956c-4cf95d479851
5c701200-14d0-11ef-956c-4cf95d479851
5c70126e-14d0-11ef-956c-4cf95d479851
5c7012d2-14d0-11ef-956c-4cf95d479851
5c701336-14d0-11ef-956c-4cf95d479851
5c70139a-14d0-11ef-956c-4cf95d479851
5c7013fe-14d0-11ef-956c-4cf95d479851
5c701458-14d0-11ef-956c-4cf95d479851
5c7014bc-14d0-11ef-956c-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)

99a7d628-0116-808b-87e8-5ce32bd83b96
57efd728-0116-808b-87e8-5ce32bd83b96
bf86d828-0116-808b-87e8-5ce32bd83b96
c453d928-0116-808b-87e8-5ce32bd83b96
4d30da28-0116-808b-87e8-5ce32bd83b96
4bbadb28-0116-808b-87e8-5ce32bd83b96
3578dc28-0116-808b-87e8-5ce32bd83b96
7e8add28-0116-808b-87e8-5ce32bd83b96
a7dfde28-0116-808b-87e8-5ce32bd83b96
5394df28-0116-808b-87e8-5ce32bd83b96
9fede028-0116-808b-87e8-5ce32bd83b96
2154e128-0116-808b-87e8-5ce32bd83b96
4c8be228-0116-808b-87e8-5ce32bd83b96
06dce328-0116-808b-87e8-5ce32bd83b96
5424e428-0116-808b-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: