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)

019e1116-a4d9-75aa-bad4-16c0427330d9
019e1116-a4d9-7734-9183-311bc643f646
019e1116-a4d9-7873-86c0-030ac1c12528
019e1116-a4d9-798e-be30-9bee8bf65b2d
019e1116-a4d9-7aa8-9913-1ae4026d46ef
019e1116-a4d9-7bbf-82d4-8c1a4a57fb24
019e1116-a4d9-7cd5-9d86-affc65ec1471
019e1116-a4d9-7dec-91eb-087fcb228a26
019e1116-a4d9-7efe-989a-73c7b72d0119
019e1116-a4da-7015-8a05-3333c29138c2
019e1116-a4da-708c-ac2d-9cd3b2bda451
019e1116-a4da-71a2-bb97-6424c0e4ba3a
019e1116-a4da-72b9-bc60-f38798d080a7
019e1116-a4da-73cb-a5fa-ac4488bb6f01
019e1116-a4da-74e2-ae3b-08404ff33fac

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)

1f14c4d9-808d-635e-8aac-4cf95d479851
1f14c4d9-808d-64f8-8aac-4cf95d479851
1f14c4d9-808d-65e8-8aac-4cf95d479851
1f14c4d9-808d-66ba-8aac-4cf95d479851
1f14c4d9-808d-678c-8aac-4cf95d479851
1f14c4d9-808d-6854-8aac-4cf95d479851
1f14c4d9-808d-691c-8aac-4cf95d479851
1f14c4d9-808d-69da-8aac-4cf95d479851
1f14c4d9-808d-6aa2-8aac-4cf95d479851
1f14c4d9-808d-6b60-8aac-4cf95d479851
1f14c4d9-808d-6ca0-8aac-4cf95d479851
1f14c4d9-808d-6d72-8aac-4cf95d479851
1f14c4d9-808d-6e3a-8aac-4cf95d479851
1f14c4d9-808d-6ef8-8aac-4cf95d479851
1f14c4d9-808d-6fb6-8aac-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)

b225685a-232e-4d9e-b61f-14ed47d57cf3
e5d8346d-2324-4f86-8f54-27d573ec82aa
a0e224aa-64a8-4663-8810-acdc8bdf8e6b
3e1f7d07-ddb8-420a-98a0-68e935d3b78c
c19d183b-ce9c-4af6-b0d8-369f1ceb7133
dea00efe-6b9a-4e7f-9688-0a027e80816b
75077a32-cd81-4994-88dc-80e87bca2739
d8f9d0e5-fc1c-4527-aba3-f99732a1a35e
3f125616-c805-45f5-8bb2-cdd599f6345c
a6067baf-230c-4aba-a748-8bdbdcfd7f5f
11f7240a-4154-4991-8f64-23a11e74f988
2aad8dc8-4ea1-414e-86f5-4b3cb7810c25
4bfc4676-8441-4ae7-aecc-6e519b212b90
1b87362e-7cad-4bc5-9f72-0b48c7e921e0
376445e0-9a16-409b-9a51-669cd716b42a

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)

9808e4de-4c4d-11f1-8aac-4cf95d479851
9808e54c-4c4d-11f1-8aac-4cf95d479851
9808e5b0-4c4d-11f1-8aac-4cf95d479851
9808e614-4c4d-11f1-8aac-4cf95d479851
9808e678-4c4d-11f1-8aac-4cf95d479851
9808e6dc-4c4d-11f1-8aac-4cf95d479851
9808e740-4c4d-11f1-8aac-4cf95d479851
9808e79a-4c4d-11f1-8aac-4cf95d479851
9808e7fe-4c4d-11f1-8aac-4cf95d479851
9808e862-4c4d-11f1-8aac-4cf95d479851
9808e8bc-4c4d-11f1-8aac-4cf95d479851
9808e920-4c4d-11f1-8aac-4cf95d479851
9808e984-4c4d-11f1-8aac-4cf95d479851
9808e9de-4c4d-11f1-8aac-4cf95d479851
9808ea4c-4c4d-11f1-8aac-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)

637c3625-1502-8208-87ea-5ce32bd83b97
31a13725-1502-8208-87ea-5ce32bd83b97
16583825-1502-8208-87ea-5ce32bd83b97
c2723925-1502-8208-87ea-5ce32bd83b97
19533a25-1502-8208-87ea-5ce32bd83b97
6b2d3b25-1502-8208-87ea-5ce32bd83b97
751d3c25-1502-8208-87ea-5ce32bd83b97
02463d25-1502-8208-87ea-5ce32bd83b97
1a0b3e25-1502-8208-87ea-5ce32bd83b97
c35f3f25-1502-8208-87ea-5ce32bd83b97
ca1a4025-1502-8208-87ea-5ce32bd83b97
96874125-1502-8208-87ea-5ce32bd83b97
d2a84225-1502-8208-87ea-5ce32bd83b97
38684325-1502-8208-87ea-5ce32bd83b97
273c4425-1502-8208-87ea-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: