UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a09559-4213-77aa-beef-8fedafbeb7b7
01a09559-4213-7950-92a0-d11d0b719a8d
01a09559-4213-7a90-9949-ed32f40da6e2
01a09559-4213-7baa-9e50-38a9466e39e0
01a09559-4213-7cc1-a17a-ffbd040b02e2
01a09559-4213-7dd8-8688-070afa365f1b
01a09559-4213-7eea-be63-0ce3cad6eb7d
01a09559-4213-7009-ba24-fda7199a2bdf
01a09559-4214-7123-9c48-3c9d02ac7b63
01a09559-4214-7236-a738-722903806844
01a09559-4214-7348-b8d5-feb1377a4680
01a09559-4214-745f-b6a0-cf945d62c153
01a09559-4214-7571-a5ac-c6bf180e820e
01a09559-4214-7684-a1aa-e752331222d0
01a09559-4214-7796-9170-8785352abb90

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)

1f1ae9c0-2268-63de-b879-4cf95d479851
1f1ae9c0-2268-65aa-b879-4cf95d479851
1f1ae9c0-2268-669a-b879-4cf95d479851
1f1ae9c0-2268-6762-b879-4cf95d479851
1f1ae9c0-2268-682a-b879-4cf95d479851
1f1ae9c0-2268-68f2-b879-4cf95d479851
1f1ae9c0-2268-69a6-b879-4cf95d479851
1f1ae9c0-2268-6a6e-b879-4cf95d479851
1f1ae9c0-2268-6b2c-b879-4cf95d479851
1f1ae9c0-2268-6bf4-b879-4cf95d479851
1f1ae9c0-2268-6d48-b879-4cf95d479851
1f1ae9c0-2268-6e1a-b879-4cf95d479851
1f1ae9c0-2268-6ed8-b879-4cf95d479851
1f1ae9c0-2268-6f96-b879-4cf95d479851
1f1ae9c0-2269-6054-b879-4cf95d479851

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)

02269126-ae9c-11f1-b879-4cf95d479851
02269194-ae9c-11f1-b879-4cf95d479851
022691ee-ae9c-11f1-b879-4cf95d479851
02269248-ae9c-11f1-b879-4cf95d479851
022692ac-ae9c-11f1-b879-4cf95d479851
02269310-ae9c-11f1-b879-4cf95d479851
02269374-ae9c-11f1-b879-4cf95d479851
022693ce-ae9c-11f1-b879-4cf95d479851
02269432-ae9c-11f1-b879-4cf95d479851
02269496-ae9c-11f1-b879-4cf95d479851
022694fa-ae9c-11f1-b879-4cf95d479851
0226955e-ae9c-11f1-b879-4cf95d479851
022695b8-ae9c-11f1-b879-4cf95d479851
0226961c-ae9c-11f1-b879-4cf95d479851
02269676-ae9c-11f1-b879-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

67fdf031-a902-8f0f-87ea-5ce32bd83b97
6cc8f131-a902-8f0f-87ea-5ce32bd83b97
dd52f231-a902-8f0f-87ea-5ce32bd83b97
fbddf331-a902-8f0f-87ea-5ce32bd83b97
5968f431-a902-8f0f-87ea-5ce32bd83b97
1a66f531-a902-8f0f-87ea-5ce32bd83b97
d49ff631-a902-8f0f-87ea-5ce32bd83b97
a093f731-a902-8f0f-87ea-5ce32bd83b97
dcedf831-a902-8f0f-87ea-5ce32bd83b97
054cf931-a902-8f0f-87ea-5ce32bd83b97
da4efa31-a902-8f0f-87ea-5ce32bd83b97
5838fb31-a902-8f0f-87ea-5ce32bd83b97
da61fd31-a902-8f0f-87ea-5ce32bd83b97
52a7fe31-a902-8f0f-87ea-5ce32bd83b97
f92bff31-a902-8f0f-87ea-5ce32bd83b97

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)

c560833b-b0d0-414f-9228-8b234474525f
8139add6-d80c-4207-80a4-8ee6cd4f65f4
5ea5d962-3f45-4a77-b657-5446daa30c5e
cc49d114-3e8f-43cf-bd14-422799657bf9
1b02a8fc-5af3-4170-bd00-c409a6a9a091
fb8e643b-3efb-4c7e-8515-f7b7eaa186a6
b7820422-f260-44e6-b71a-edb3bb91adf6
3ece09f6-f5e8-4163-bb7b-f6361db79852
05acc7b7-7901-4dd3-90c2-112aebd94fba
a43d0c72-0320-4c82-8cf2-28b319c81a4b
06155097-b063-40e0-bb26-d87ba484c1aa
ebbe099a-9eec-401c-8171-95b59f4a1c47
1f58fcd5-2de5-4c7b-ae91-49fe358a211c
0d194d18-bcf2-46ae-88ea-6971b61e78cd
4a682bff-56eb-4087-bcb7-827fe57f7dff

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: