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)

019c9843-50e8-7a21-b22e-fc1df88e13a1
019c9843-50e8-7cee-98a9-28d8707ddabd
019c9843-50e8-7e5b-9d30-ebd7ebd5ca43
019c9843-50e8-7f82-8555-847c6fe9dc85
019c9843-50e9-709c-aa0b-1052f109a4ba
019c9843-50e9-71bb-ba60-960b44880360
019c9843-50e9-72d1-8a0d-ea75c325261e
019c9843-50e9-73f0-bc25-687da2d66a1c
019c9843-50e9-750b-a5eb-6c4c19f815c8
019c9843-50e9-7625-a4cf-418a96c9e626
019c9843-50e9-7744-a7ed-4b13184a08f9
019c9843-50e9-7863-bde9-08c0717a4073
019c9843-50e9-7979-affd-6ae75e2d689f
019c9843-50e9-7a94-9aed-e30a08bbbdf8
019c9843-50e9-7bd8-a6f1-aa632e2cc0b6

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)

1f112cdd-909e-6ed8-9863-4cf95d479851
1f112cdd-909f-60cc-9863-4cf95d479851
1f112cdd-909f-61bc-9863-4cf95d479851
1f112cdd-909f-6298-9863-4cf95d479851
1f112cdd-909f-6360-9863-4cf95d479851
1f112cdd-909f-643c-9863-4cf95d479851
1f112cdd-909f-6504-9863-4cf95d479851
1f112cdd-909f-65cc-9863-4cf95d479851
1f112cdd-909f-669e-9863-4cf95d479851
1f112cdd-909f-6766-9863-4cf95d479851
1f112cdd-909f-68d8-9863-4cf95d479851
1f112cdd-909f-69aa-9863-4cf95d479851
1f112cdd-909f-6a72-9863-4cf95d479851
1f112cdd-909f-6b3a-9863-4cf95d479851
1f112cdd-909f-6c0c-9863-4cf95d479851

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)

86c84845-3d5a-40ef-bcd1-65460bb4260e
240e8da1-166b-4992-83db-83b5bca4142f
9b9314f1-96d6-4fc4-be52-de037625c04d
0a320d89-1e90-492d-8212-0d5fc432b4d6
9619bd78-6909-486d-a8f2-2439ca93d57a
338f6d34-5de0-4bd6-9cf0-3fba51d3bed0
147c5aa9-c156-46f0-841b-9c789352481c
9b2da1d0-c2b3-4197-aff6-83ba3acac880
a04d2c20-55bf-4bd8-8401-ecbda7c14392
8f006447-e62a-4022-999f-5e2fbde1d2a7
d92180fc-fc19-42c6-aaf7-e2be0c562cf2
bf12a5b7-8509-4919-9500-2c6b093359ac
f045bfd0-e310-40f3-973f-2ca9f074da26
efa71de9-d6e5-4a41-85c6-7775807bf98f
41a5c3b0-e2da-44c8-8e29-80452b80d60d

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)

d90a0148-12cd-11f1-9863-4cf95d479851
d90a01ac-12cd-11f1-9863-4cf95d479851
d90a0210-12cd-11f1-9863-4cf95d479851
d90a027e-12cd-11f1-9863-4cf95d479851
d90a02e2-12cd-11f1-9863-4cf95d479851
d90a033c-12cd-11f1-9863-4cf95d479851
d90a03a0-12cd-11f1-9863-4cf95d479851
d90a03fa-12cd-11f1-9863-4cf95d479851
d90a0472-12cd-11f1-9863-4cf95d479851
d90a04e0-12cd-11f1-9863-4cf95d479851
d90a054e-12cd-11f1-9863-4cf95d479851
d90a05bc-12cd-11f1-9863-4cf95d479851
d90a062a-12cd-11f1-9863-4cf95d479851
d90a068e-12cd-11f1-9863-4cf95d479851
d90a06fc-12cd-11f1-9863-4cf95d479851

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)

a0486922-1d01-8903-87ea-5ce32bd83b97
e2bb6a22-1d01-8903-87ea-5ce32bd83b97
96106b22-1d01-8903-87ea-5ce32bd83b97
32976c22-1d01-8903-87ea-5ce32bd83b97
42056d22-1d01-8903-87ea-5ce32bd83b97
879f6e22-1d01-8903-87ea-5ce32bd83b97
40b46f22-1d01-8903-87ea-5ce32bd83b97
ae1f7022-1d01-8903-87ea-5ce32bd83b97
03d57122-1d01-8903-87ea-5ce32bd83b97
781f7222-1d01-8903-87ea-5ce32bd83b97
98d67322-1d01-8903-87ea-5ce32bd83b97
ed5e7422-1d01-8903-87ea-5ce32bd83b97
22c07522-1d01-8903-87ea-5ce32bd83b97
0c407622-1d01-8903-87ea-5ce32bd83b97
11bb7722-1d01-8903-87ea-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: