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)

019c0afc-ca59-7a8c-a2cd-c359adffdacf
019c0afc-ca59-7c19-868f-f2c55fd3f7b9
019c0afc-ca59-7d5d-9610-0d4f1e05b2ad
019c0afc-ca59-7e7f-860b-3bb12552cffd
019c0afc-ca59-7f9e-936a-4fdda7f62749
019c0afc-ca5a-70b9-a2ff-503fbecb2767
019c0afc-ca5a-71d8-90c0-1a7dffb48ed9
019c0afc-ca5a-72f2-bd6f-0a5782954371
019c0afc-ca5a-7411-ad43-2fbae6d87d06
019c0afc-ca5a-752c-be48-4ae86d29e9c2
019c0afc-ca5a-7646-a6b9-a4aba8609beb
019c0afc-ca5a-7761-8041-692886af66df
019c0afc-ca5a-787b-a52e-0d231bdb2cce
019c0afc-ca5a-7996-a060-5366e61364cf
019c0afc-ca5a-7ab5-b048-e22ff5686f05

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)

1f0fd3f4-621b-69dc-85ea-4cf95d479851
1f0fd3f4-621b-6b6c-85ea-4cf95d479851
1f0fd3f4-621b-6c5c-85ea-4cf95d479851
1f0fd3f4-621b-6d2e-85ea-4cf95d479851
1f0fd3f4-621b-6e00-85ea-4cf95d479851
1f0fd3f4-621b-6ec8-85ea-4cf95d479851
1f0fd3f4-621b-6f9a-85ea-4cf95d479851
1f0fd3f4-621c-6062-85ea-4cf95d479851
1f0fd3f4-621c-612a-85ea-4cf95d479851
1f0fd3f4-621c-61f2-85ea-4cf95d479851
1f0fd3f4-621c-633c-85ea-4cf95d479851
1f0fd3f4-621c-640e-85ea-4cf95d479851
1f0fd3f4-621c-64d6-85ea-4cf95d479851
1f0fd3f4-621c-659e-85ea-4cf95d479851
1f0fd3f4-621c-6666-85ea-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)

4996eeb4-342a-4675-9a14-fe9ed66b470d
f900a1ed-555c-4dae-af88-abb28942d19b
e17f3a17-cebc-419b-90bd-97ebfb17f625
24113e8c-a80d-4c05-bf81-f5771cbd5b95
ca2d1dc1-5d97-4a7d-b101-120c9a3716d7
93353cfc-65e6-4d70-9c07-f2d1cb197783
bb6b33a4-a3d3-44cb-8063-992c71a42fc8
e707e786-918c-490f-86b4-51d0848e4e5a
55f5abae-caf2-4640-817c-01386d20ecb6
3717bcf1-ee6b-4458-a315-7a964f4ae932
6e4c3b28-d6be-4d70-b002-a94b6d75e9da
fdc308c2-292a-4b93-8c18-913ba206fc85
38c7c822-8d90-4f68-83d7-c19762717c51
732e62c2-5513-41c9-8cc7-1870e0572f35
8dc16ca6-1625-48ec-84c1-92c7fc0c76bb

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)

4621cb84-fd3f-11f0-85ea-4cf95d479851
4621cbf2-fd3f-11f0-85ea-4cf95d479851
4621cc4c-fd3f-11f0-85ea-4cf95d479851
4621ccb0-fd3f-11f0-85ea-4cf95d479851
4621cd14-fd3f-11f0-85ea-4cf95d479851
4621cd78-fd3f-11f0-85ea-4cf95d479851
4621cdd2-fd3f-11f0-85ea-4cf95d479851
4621ce36-fd3f-11f0-85ea-4cf95d479851
4621ce90-fd3f-11f0-85ea-4cf95d479851
4621cefe-fd3f-11f0-85ea-4cf95d479851
4621cf6c-fd3f-11f0-85ea-4cf95d479851
4621cfd0-fd3f-11f0-85ea-4cf95d479851
4621d034-fd3f-11f0-85ea-4cf95d479851
4621d098-fd3f-11f0-85ea-4cf95d479851
4621d0fc-fd3f-11f0-85ea-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)

b691fc04-4e04-8d01-87ea-5ce32bd83b97
ad74fd04-4e04-8d01-87ea-5ce32bd83b97
190bfe04-4e04-8d01-87ea-5ce32bd83b97
6748ff04-4e04-8d01-87ea-5ce32bd83b97
5bf20105-4e04-8d01-87ea-5ce32bd83b97
74520205-4e04-8d01-87ea-5ce32bd83b97
9a1f0305-4e04-8d01-87ea-5ce32bd83b97
da9d0405-4e04-8d01-87ea-5ce32bd83b97
c4b70505-4e04-8d01-87ea-5ce32bd83b97
8ed50605-4e04-8d01-87ea-5ce32bd83b97
931b0705-4e04-8d01-87ea-5ce32bd83b97
a6a90805-4e04-8d01-87ea-5ce32bd83b97
34e30905-4e04-8d01-87ea-5ce32bd83b97
ffcc0a05-4e04-8d01-87ea-5ce32bd83b97
f0a40b05-4e04-8d01-87ea-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: