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)

019a820a-a2cb-7c5f-8bc3-fb5c9e0e01ad
019a820a-a2cb-7dec-9a1c-5ebe0457294a
019a820a-a2cb-7f30-95e8-24c3d7d23362
019a820a-a2cc-7052-8e7b-7dc2880b2e88
019a820a-a2cc-7171-8335-ba38f214494b
019a820a-a2cc-7290-ba44-f9d42ab7f6a5
019a820a-a2cc-73aa-bc5b-b2dd407a3d72
019a820a-a2cc-74c9-9751-7c0baabc35bc
019a820a-a2cc-75e4-a67c-397728e59d8a
019a820a-a2cc-76fe-bb99-e821d7c8c096
019a820a-a2cc-7819-9fab-c157b8b933ad
019a820a-a2cc-7934-a82b-08149a5a1cf2
019a820a-a2cc-7a52-8eb9-60389b3e86a8
019a820a-a2cc-7b6d-8e20-253319f57eef
019a820a-a2cc-7ce2-81dd-f420d46ef2b9

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)

1f0c149d-2f8a-64a6-98bf-4cf95d479851
1f0c149d-2f8a-6672-98bf-4cf95d479851
1f0c149d-2f8a-6762-98bf-4cf95d479851
1f0c149d-2f8a-6848-98bf-4cf95d479851
1f0c149d-2f8a-6924-98bf-4cf95d479851
1f0c149d-2f8a-69f6-98bf-4cf95d479851
1f0c149d-2f8a-6ac8-98bf-4cf95d479851
1f0c149d-2f8a-6b9a-98bf-4cf95d479851
1f0c149d-2f8a-6c6c-98bf-4cf95d479851
1f0c149d-2f8a-6d34-98bf-4cf95d479851
1f0c149d-2f8a-6e7e-98bf-4cf95d479851
1f0c149d-2f8a-6f50-98bf-4cf95d479851
1f0c149d-2f8b-6022-98bf-4cf95d479851
1f0c149d-2f8b-60f4-98bf-4cf95d479851
1f0c149d-2f8b-61c6-98bf-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)

69fa0234-9761-413f-9761-88d599296195
c2f86007-3022-4119-b594-8af1deb6027b
5567dce0-6cf1-4601-b36d-fe9bd8a26c73
f943c0ad-eb59-4a82-919f-f0bf6b3ed67a
5cf2ff1c-333f-404b-889a-41e80a5eb755
f4fdc70d-70c4-496f-81b7-d8e529dbd3d7
1f938e23-947e-474a-863d-1a4964be80f6
8a377f79-f39f-4b3c-8d8a-7351de16293f
0519c8b9-77ee-43bc-a4f9-f6148d42dc47
1a3d66a5-8a3c-4e53-a3f6-cf374a6b20ff
b9507116-85e9-46d4-9d0d-300ee9d1d8b5
e9da8437-2733-4886-a6b8-a9f2201f9c57
5575ec67-99d1-4cf3-9dba-5e8aa440404e
6cb1e856-e88d-4ed7-9124-5417baa5a7d5
d651e546-3a6f-4b32-9b7e-d683c7d463b4

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)

d2f8b702-c149-11f0-98bf-4cf95d479851
d2f8b770-c149-11f0-98bf-4cf95d479851
d2f8b7d4-c149-11f0-98bf-4cf95d479851
d2f8b838-c149-11f0-98bf-4cf95d479851
d2f8b89c-c149-11f0-98bf-4cf95d479851
d2f8b900-c149-11f0-98bf-4cf95d479851
d2f8b964-c149-11f0-98bf-4cf95d479851
d2f8b9c8-c149-11f0-98bf-4cf95d479851
d2f8ba2c-c149-11f0-98bf-4cf95d479851
d2f8ba9a-c149-11f0-98bf-4cf95d479851
d2f8bb08-c149-11f0-98bf-4cf95d479851
d2f8bb76-c149-11f0-98bf-4cf95d479851
d2f8bbda-c149-11f0-98bf-4cf95d479851
d2f8bc48-c149-11f0-98bf-4cf95d479851
d2f8bcac-c149-11f0-98bf-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)

43547a1a-9a02-8e13-87e9-5ce32bd83b97
9f597b1a-9a02-8e13-87e9-5ce32bd83b97
d68b7c1a-9a02-8e13-87e9-5ce32bd83b97
a1217d1a-9a02-8e13-87e9-5ce32bd83b97
97ef7e1a-9a02-8e13-87e9-5ce32bd83b97
5f757f1a-9a02-8e13-87e9-5ce32bd83b97
b52e801a-9a02-8e13-87e9-5ce32bd83b97
6829811a-9a02-8e13-87e9-5ce32bd83b97
7ffb821a-9a02-8e13-87e9-5ce32bd83b97
bd5d831a-9a02-8e13-87e9-5ce32bd83b97
2f96841a-9a02-8e13-87e9-5ce32bd83b97
6359851a-9a02-8e13-87e9-5ce32bd83b97
1381861a-9a02-8e13-87e9-5ce32bd83b97
5d80871a-9a02-8e13-87e9-5ce32bd83b97
0f00881a-9a02-8e13-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: