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)

019bc0cc-e5c2-7619-847a-8ac80ed16d56
019bc0cc-e5c2-77b7-97c3-beb0ef43e3c5
019bc0cc-e5c2-78fa-bb0a-570cb72eb966
019bc0cc-e5c2-7a25-a617-8122ab69ab40
019bc0cc-e5c2-7b44-8fe6-98040b71f0ed
019bc0cc-e5c2-7c63-b838-a10e8e891770
019bc0cc-e5c2-7d86-a245-67eab5d1e137
019bc0cc-e5c2-7ea0-9035-8d722a162e73
019bc0cc-e5c2-7fbf-82da-539fa1839d6b
019bc0cc-e5c3-70de-89ea-982d2efa6c56
019bc0cc-e5c3-7229-a7d1-94e07d95e520
019bc0cc-e5c3-7361-b128-15aad514efb0
019bc0cc-e5c3-7484-aa58-057f5a4209cf
019bc0cc-e5c3-75a6-864e-d3ef1d78ba77
019bc0cc-e5c3-76c5-9e3f-ebc4a51c88de

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)

1f0f1ed5-7506-659e-bb08-4cf95d479851
1f0f1ed5-7506-674c-bb08-4cf95d479851
1f0f1ed5-7506-6846-bb08-4cf95d479851
1f0f1ed5-7506-6922-bb08-4cf95d479851
1f0f1ed5-7506-69fe-bb08-4cf95d479851
1f0f1ed5-7506-6ad0-bb08-4cf95d479851
1f0f1ed5-7506-6ba2-bb08-4cf95d479851
1f0f1ed5-7506-6c74-bb08-4cf95d479851
1f0f1ed5-7506-6d3c-bb08-4cf95d479851
1f0f1ed5-7506-6e0e-bb08-4cf95d479851
1f0f1ed5-7506-6f58-bb08-4cf95d479851
1f0f1ed5-7507-6034-bb08-4cf95d479851
1f0f1ed5-7507-6106-bb08-4cf95d479851
1f0f1ed5-7507-61d8-bb08-4cf95d479851
1f0f1ed5-7507-62aa-bb08-4cf95d479851

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)

dee1b7bf-04c7-42b7-9ae7-2967edbc1bb6
073de00b-5706-47fd-b94e-1defd4d4849b
d6863d84-4e82-4dd5-b36a-a15ce9aee64d
15627848-4091-49cd-ad41-1ebfc31da4ca
ae8e1dbe-cafa-418c-90d6-d1030f1f6d0a
ff903297-1296-4503-822f-82e31769a768
fd0d9773-4280-4f74-9154-d308118e4fb0
3755d333-98a9-4e25-96e9-da1054b4f69c
63dd5005-43af-4aa9-bf4d-bca599a3539b
5c6e2e50-85f2-47e5-9405-ede09896620e
f3b867de-5317-4451-8706-7c7a777e4936
4d2eeef6-50d0-4b9a-bb0c-fcf7d412a43e
7a2c6a9e-dc0a-42b0-9938-f31c533d218f
e8eb907f-f6da-4aa6-993f-b6ba9651a77c
3f1b5ccb-8d48-4620-81c0-8c85b7a312f1

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)

575077d2-f1ed-11f0-bb08-4cf95d479851
57507836-f1ed-11f0-bb08-4cf95d479851
575078a4-f1ed-11f0-bb08-4cf95d479851
57507908-f1ed-11f0-bb08-4cf95d479851
5750796c-f1ed-11f0-bb08-4cf95d479851
575079d0-f1ed-11f0-bb08-4cf95d479851
57507a34-f1ed-11f0-bb08-4cf95d479851
57507a98-f1ed-11f0-bb08-4cf95d479851
57507afc-f1ed-11f0-bb08-4cf95d479851
57507b56-f1ed-11f0-bb08-4cf95d479851
57507bba-f1ed-11f0-bb08-4cf95d479851
57507c14-f1ed-11f0-bb08-4cf95d479851
57507c78-f1ed-11f0-bb08-4cf95d479851
57507cd2-f1ed-11f0-bb08-4cf95d479851
57507d36-f1ed-11f0-bb08-4cf95d479851

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)

89564b34-0502-8f00-87ea-5ce32bd83b97
676b4c34-0502-8f00-87ea-5ce32bd83b97
ef2e4d34-0502-8f00-87ea-5ce32bd83b97
12074e34-0502-8f00-87ea-5ce32bd83b97
31624f34-0502-8f00-87ea-5ce32bd83b97
0f5c5034-0502-8f00-87ea-5ce32bd83b97
c9b25134-0502-8f00-87ea-5ce32bd83b97
91eb5234-0502-8f00-87ea-5ce32bd83b97
611c5334-0502-8f00-87ea-5ce32bd83b97
4fab5434-0502-8f00-87ea-5ce32bd83b97
8a405534-0502-8f00-87ea-5ce32bd83b97
06595634-0502-8f00-87ea-5ce32bd83b97
49c85734-0502-8f00-87ea-5ce32bd83b97
63265834-0502-8f00-87ea-5ce32bd83b97
a5b85934-0502-8f00-87ea-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: