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)

019f0491-fa96-7673-9b26-200348ff39d1
019f0491-fa96-783e-8f06-73d52552f540
019f0491-fa96-79b7-bf03-f0bc6168ab13
019f0491-fa96-7afa-8f7c-623b82a1d9b2
019f0491-fa96-7c42-a174-e9343f00b4ae
019f0491-fa96-7d9e-83b8-e9876d2defd3
019f0491-fa96-7eee-a3db-273ecf1e7ae7
019f0491-fa97-7032-baa3-0bb12c9e08fe
019f0491-fa97-7175-bcff-fba78bdea3f5
019f0491-fa97-72ad-9263-b35ed3c3af19
019f0491-fa97-73e4-92b3-76ec3d8717ec
019f0491-fa97-7534-b498-e618bcd5d41d
019f0491-fa97-7684-a5be-4c184a6085fe
019f0491-fa97-77d3-83ce-720ca0b674eb
019f0491-fa97-7913-89c8-75eada67f2b1

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)

1f171749-9ce0-6604-a4d6-4cf95d479851
1f171749-9ce0-68ac-a4d6-4cf95d479851
1f171749-9ce0-6a3c-a4d6-4cf95d479851
1f171749-9ce0-6bcc-a4d6-4cf95d479851
1f171749-9ce0-6d3e-a4d6-4cf95d479851
1f171749-9ce0-6eb0-a4d6-4cf95d479851
1f171749-9ce1-6018-a4d6-4cf95d479851
1f171749-9ce1-6180-a4d6-4cf95d479851
1f171749-9ce1-62de-a4d6-4cf95d479851
1f171749-9ce1-643c-a4d6-4cf95d479851
1f171749-9ce1-668a-a4d6-4cf95d479851
1f171749-9ce1-67fc-a4d6-4cf95d479851
1f171749-9ce1-6950-a4d6-4cf95d479851
1f171749-9ce1-6aae-a4d6-4cf95d479851
1f171749-9ce1-6c02-a4d6-4cf95d479851

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)

99ce1d74-7174-11f1-a4d6-4cf95d479851
99ce1e14-7174-11f1-a4d6-4cf95d479851
99ce1eb4-7174-11f1-a4d6-4cf95d479851
99ce1f4a-7174-11f1-a4d6-4cf95d479851
99ce1fe0-7174-11f1-a4d6-4cf95d479851
99ce2080-7174-11f1-a4d6-4cf95d479851
99ce212a-7174-11f1-a4d6-4cf95d479851
99ce21c0-7174-11f1-a4d6-4cf95d479851
99ce2256-7174-11f1-a4d6-4cf95d479851
99ce22ec-7174-11f1-a4d6-4cf95d479851
99ce2382-7174-11f1-a4d6-4cf95d479851
99ce2422-7174-11f1-a4d6-4cf95d479851
99ce24b8-7174-11f1-a4d6-4cf95d479851
99ce254e-7174-11f1-a4d6-4cf95d479851
99ce25ee-7174-11f1-a4d6-4cf95d479851

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)

75b99303-a803-810b-87ea-5ce32bd83b97
cad99403-a803-810b-87ea-5ce32bd83b97
f5a99503-a803-810b-87ea-5ce32bd83b97
efa59603-a803-810b-87ea-5ce32bd83b97
dab59703-a803-810b-87ea-5ce32bd83b97
a1c99803-a803-810b-87ea-5ce32bd83b97
7ff09903-a803-810b-87ea-5ce32bd83b97
81779a03-a803-810b-87ea-5ce32bd83b97
05da9b03-a803-810b-87ea-5ce32bd83b97
27c79c03-a803-810b-87ea-5ce32bd83b97
faf99d03-a803-810b-87ea-5ce32bd83b97
08f29f03-a803-810b-87ea-5ce32bd83b97
c5c1a003-a803-810b-87ea-5ce32bd83b97
21e7a103-a803-810b-87ea-5ce32bd83b97
3829a203-a803-810b-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)

f9c96511-5381-434e-8342-fa640a2737a4
1722a282-1c9f-4789-9198-16aa31593df0
206094fa-9ea0-46e7-a318-b7b9feaf9479
18bb64f2-74c6-4cd5-a16b-f3373e55e7a7
e58d58b9-33eb-4fea-9f5e-1a4f02971b5b
f042622d-5b4b-428f-be5a-70b77885d7fe
ca36950a-9d4f-4aad-bfc9-8dcf74777801
2adcaea8-6bf4-41b5-a57b-3d05c5b6d061
3eeeb09e-412f-4bde-9a61-312a76d5090e
e89e24b5-f78a-4261-8472-97acd4fd5ff3
4fffefa4-9bd7-4160-9bb7-2f7822d7e6a6
1e1e7a88-386e-40af-b8cd-21e3b2da6c6b
ccf708b5-b9a5-4cdf-b6b6-dbb0f7f308af
b2199281-6534-4c23-aecd-0b141b7b071c
cf63bb40-d16d-44fa-be6e-6d56458fede7

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: