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)

019c58f7-98ec-7dc7-8183-f959a4497d19
019c58f7-98ec-7fa2-9a4b-40b08d3c63b4
019c58f7-98ed-7134-901e-a032018e3d6c
019c58f7-98ed-7298-84b5-3c14ca378080
019c58f7-98ed-73f8-baf2-46bda81d3a6b
019c58f7-98ed-7550-9f9e-f6cd94aa30c8
019c58f7-98ed-76a4-a757-df11f2d62ef5
019c58f7-98ed-77fc-8858-3b62e2503f35
019c58f7-98ed-7959-9335-f7ab3e41c230
019c58f7-98ed-7aa4-b08b-027830c04000
019c58f7-98ed-7bf8-a788-73684cd21969
019c58f7-98ed-7d4c-99f7-1d455d7642aa
019c58f7-98ed-7ea8-a469-9222577f8564
019c58f7-98ed-7005-b3f6-16d4ecf6a9cb
019c58f7-98ee-715d-b9d0-e71c5e7b0e1d

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)

1f109255-b471-689c-8afa-4cf95d479851
1f109255-b471-6aa4-8afa-4cf95d479851
1f109255-b471-6bee-8afa-4cf95d479851
1f109255-b471-6d2e-8afa-4cf95d479851
1f109255-b471-6e78-8afa-4cf95d479851
1f109255-b471-6fe0-8afa-4cf95d479851
1f109255-b472-6134-8afa-4cf95d479851
1f109255-b472-62b0-8afa-4cf95d479851
1f109255-b472-640e-8afa-4cf95d479851
1f109255-b472-6576-8afa-4cf95d479851
1f109255-b472-6788-8afa-4cf95d479851
1f109255-b472-68dc-8afa-4cf95d479851
1f109255-b472-6a26-8afa-4cf95d479851
1f109255-b472-6b98-8afa-4cf95d479851
1f109255-b472-6d00-8afa-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)

761216b7-e140-46ec-9f89-c01e91579945
eb439b33-e8cb-415d-b6df-ec1dd3bbc13a
0d06fa40-b40a-4744-945f-96750b95f73f
d37b2933-7b8a-443c-aeb8-7cfcdb57ab39
73743681-a005-48f0-9db8-85ca8484a0b4
24ea4c47-0184-46e8-ba1f-fdc46b8f6904
423c0ae7-1655-48a5-9368-7d5489898370
0eff63db-eedf-4339-aa68-26e92d5cb355
c758d1af-343e-44c1-8e73-ef362715370f
f18df590-b604-4e51-89b2-b2cb370b8cef
0e3f80dc-4ab9-462e-ba5c-7dc3854d1c4c
fcbe201d-69ed-4a86-94bf-09ce5abc30fe
2b4e1aa1-8f52-4b69-85e1-0a485a05b29f
84043f44-3931-4bad-97d5-90d35baafef0
9f5eb613-58dd-4124-bc70-46165aa353b6

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)

5b473516-0925-11f1-8afa-4cf95d479851
5b4735ac-0925-11f1-8afa-4cf95d479851
5b473642-0925-11f1-8afa-4cf95d479851
5b4736c4-0925-11f1-8afa-4cf95d479851
5b47375a-0925-11f1-8afa-4cf95d479851
5b4737f0-0925-11f1-8afa-4cf95d479851
5b473890-0925-11f1-8afa-4cf95d479851
5b473926-0925-11f1-8afa-4cf95d479851
5b4739bc-0925-11f1-8afa-4cf95d479851
5b473a52-0925-11f1-8afa-4cf95d479851
5b473ade-0925-11f1-8afa-4cf95d479851
5b473b74-0925-11f1-8afa-4cf95d479851
5b473c14-0925-11f1-8afa-4cf95d479851
5b473cbe-0925-11f1-8afa-4cf95d479851
5b473d54-0925-11f1-8afa-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)

9f00802f-1a05-8c02-87ea-5ce32bd83b97
3653812f-1a05-8c02-87ea-5ce32bd83b97
51c6822f-1a05-8c02-87ea-5ce32bd83b97
4951832f-1a05-8c02-87ea-5ce32bd83b97
74ef842f-1a05-8c02-87ea-5ce32bd83b97
b3ab852f-1a05-8c02-87ea-5ce32bd83b97
b038872f-1a05-8c02-87ea-5ce32bd83b97
4a5c882f-1a05-8c02-87ea-5ce32bd83b97
cb81892f-1a05-8c02-87ea-5ce32bd83b97
06ca8a2f-1a05-8c02-87ea-5ce32bd83b97
88d58b2f-1a05-8c02-87ea-5ce32bd83b97
45448c2f-1a05-8c02-87ea-5ce32bd83b97
90e88d2f-1a05-8c02-87ea-5ce32bd83b97
69d18e2f-1a05-8c02-87ea-5ce32bd83b97
ba8c8f2f-1a05-8c02-87ea-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: