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)

019c5ac7-1a0c-7f82-b3d7-b211606a53e8
019c5ac7-1a0d-713c-ad48-0b4dce45f2e3
019c5ac7-1a0d-7284-a178-84e6efd25bb8
019c5ac7-1a0d-73a6-b037-296767ac43ab
019c5ac7-1a0d-74c1-abea-4919ae3238e2
019c5ac7-1a0d-75d8-b63c-0d2dc46db695
019c5ac7-1a0d-76f2-904b-1e1ca3087f27
019c5ac7-1a0d-780d-bfd8-e8dcb4581002
019c5ac7-1a0d-7930-ba98-89395693849a
019c5ac7-1a0d-7a4a-a934-9f5331a49f9a
019c5ac7-1a0d-7b65-a1ad-f663b7fd158f
019c5ac7-1a0d-7c7f-a9e5-9f19b5795c64
019c5ac7-1a0d-7d96-b290-8f9844546c0d
019c5ac7-1a0d-7eb1-96ef-74dc3dd70190
019c5ac7-1a0d-7fcb-a48d-39e20dbada6b

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)

1f1096c1-4eb0-6650-ad4a-4cf95d479851
1f1096c1-4eb0-67ea-ad4a-4cf95d479851
1f1096c1-4eb0-68e4-ad4a-4cf95d479851
1f1096c1-4eb0-69c0-ad4a-4cf95d479851
1f1096c1-4eb0-6a92-ad4a-4cf95d479851
1f1096c1-4eb0-6b64-ad4a-4cf95d479851
1f1096c1-4eb0-6c2c-ad4a-4cf95d479851
1f1096c1-4eb0-6cf4-ad4a-4cf95d479851
1f1096c1-4eb0-6dbc-ad4a-4cf95d479851
1f1096c1-4eb0-6e84-ad4a-4cf95d479851
1f1096c1-4eb0-6fd8-ad4a-4cf95d479851
1f1096c1-4eb1-60aa-ad4a-4cf95d479851
1f1096c1-4eb1-6172-ad4a-4cf95d479851
1f1096c1-4eb1-623a-ad4a-4cf95d479851
1f1096c1-4eb1-630c-ad4a-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)

313d7963-827d-41b5-b09f-96798ede282c
a900ba7a-c484-4b12-89cd-5fee91c36556
e3f53d56-89e0-4753-a59a-7c1de881d288
b5db2f7a-1a75-4297-8185-caae27265e15
90e78ed8-c459-4210-b9e4-b57f23f3a506
cd5c501e-14f6-4784-a556-5e7810ff507e
1828b778-c72b-42f7-80dd-cac0d0bad79f
f996c03f-93f0-483b-b1ee-9adfa1898179
857a5da3-48d3-48a9-88dc-99d77e75c562
676828f9-22db-4849-94c6-7830016752f9
97e29e1b-78b7-498e-a216-625747336110
7eca3233-0b83-4641-ba02-bc2db08b4592
0ef411ed-5e2e-49ff-9f99-289c1b4f5200
cd175196-0554-4e79-813c-f5b34d40fe7f
a581d1b8-89cb-4ffb-a3d0-f5f549ba0baa

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)

14eb183e-096c-11f1-ad4a-4cf95d479851
14eb18b6-096c-11f1-ad4a-4cf95d479851
14eb191a-096c-11f1-ad4a-4cf95d479851
14eb1988-096c-11f1-ad4a-4cf95d479851
14eb19ec-096c-11f1-ad4a-4cf95d479851
14eb1a5a-096c-11f1-ad4a-4cf95d479851
14eb1abe-096c-11f1-ad4a-4cf95d479851
14eb1b36-096c-11f1-ad4a-4cf95d479851
14eb1bcc-096c-11f1-ad4a-4cf95d479851
14eb1c62-096c-11f1-ad4a-4cf95d479851
14eb1ce4-096c-11f1-ad4a-4cf95d479851
14eb1d5c-096c-11f1-ad4a-4cf95d479851
14eb1dc0-096c-11f1-ad4a-4cf95d479851
14eb1e24-096c-11f1-ad4a-4cf95d479851
14eb1e88-096c-11f1-ad4a-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)

296db903-7501-8d02-87ea-5ce32bd83b97
f970ba03-7501-8d02-87ea-5ce32bd83b97
d2febc03-7501-8d02-87ea-5ce32bd83b97
c58cbd03-7501-8d02-87ea-5ce32bd83b97
02b1be03-7501-8d02-87ea-5ce32bd83b97
0da0bf03-7501-8d02-87ea-5ce32bd83b97
0615c003-7501-8d02-87ea-5ce32bd83b97
2b3bc103-7501-8d02-87ea-5ce32bd83b97
df8ec203-7501-8d02-87ea-5ce32bd83b97
e125c303-7501-8d02-87ea-5ce32bd83b97
2ca1c403-7501-8d02-87ea-5ce32bd83b97
8e3dc503-7501-8d02-87ea-5ce32bd83b97
9982c603-7501-8d02-87ea-5ce32bd83b97
1cdfc703-7501-8d02-87ea-5ce32bd83b97
f481c803-7501-8d02-87ea-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: