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)

01a18ed5-f7f5-790f-9482-dd4c5d71fcd6
01a18ed5-f7f5-7ab1-90bf-398da26b74ae
01a18ed5-f7f5-7bf4-9e08-05f8de6374b0
01a18ed5-f7f5-7d0f-85a9-126e742116c1
01a18ed5-f7f5-7e25-9d4f-1d50ccd3c459
01a18ed5-f7f5-7f38-a10e-54a93e96eec2
01a18ed5-f7f6-7057-b73f-e47c0cebac0f
01a18ed5-f7f6-716d-83f5-22484e1843d8
01a18ed5-f7f6-727f-9570-81adb427a652
01a18ed5-f7f6-7392-a1e5-03541d28d36a
01a18ed5-f7f6-74a0-b9d3-c778b12fcf89
01a18ed5-f7f6-75b3-9b1b-0b4899597aad
01a18ed5-f7f6-76c5-8ac0-170fc1625994
01a18ed5-f7f6-77d8-803c-bfb9681e22d7
01a18ed5-f7f6-78ea-b263-3c6d225721fd

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)

1f1d4ad9-9a75-6314-a086-4cf95d479851
1f1d4ad9-9a75-64cc-a086-4cf95d479851
1f1d4ad9-9a75-65bc-a086-4cf95d479851
1f1d4ad9-9a75-668e-a086-4cf95d479851
1f1d4ad9-9a75-6760-a086-4cf95d479851
1f1d4ad9-9a75-681e-a086-4cf95d479851
1f1d4ad9-9a75-68e6-a086-4cf95d479851
1f1d4ad9-9a75-69ae-a086-4cf95d479851
1f1d4ad9-9a75-6a6c-a086-4cf95d479851
1f1d4ad9-9a75-6b34-a086-4cf95d479851
1f1d4ad9-9a75-6c74-a086-4cf95d479851
1f1d4ad9-9a75-6d46-a086-4cf95d479851
1f1d4ad9-9a75-6e0e-a086-4cf95d479851
1f1d4ad9-9a75-6ed6-a086-4cf95d479851
1f1d4ad9-9a75-6f9e-a086-4cf95d479851

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)

99a7607a-d4ad-11f1-a086-4cf95d479851
99a760de-d4ad-11f1-a086-4cf95d479851
99a7614c-d4ad-11f1-a086-4cf95d479851
99a761ba-d4ad-11f1-a086-4cf95d479851
99a7621e-d4ad-11f1-a086-4cf95d479851
99a7628c-d4ad-11f1-a086-4cf95d479851
99a762f0-d4ad-11f1-a086-4cf95d479851
99a76354-d4ad-11f1-a086-4cf95d479851
99a763b8-d4ad-11f1-a086-4cf95d479851
99a7641c-d4ad-11f1-a086-4cf95d479851
99a7648a-d4ad-11f1-a086-4cf95d479851
99a764f8-d4ad-11f1-a086-4cf95d479851
99a76552-d4ad-11f1-a086-4cf95d479851
99a765b6-d4ad-11f1-a086-4cf95d479851
99a7661a-d4ad-11f1-a086-4cf95d479851

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)

2e47c01d-2b05-8f12-87ea-5ce32bd83b97
77e8c11d-2b05-8f12-87ea-5ce32bd83b97
d2aec21d-2b05-8f12-87ea-5ce32bd83b97
79b3c31d-2b05-8f12-87ea-5ce32bd83b97
bc6ac41d-2b05-8f12-87ea-5ce32bd83b97
be8cc51d-2b05-8f12-87ea-5ce32bd83b97
2997c61d-2b05-8f12-87ea-5ce32bd83b97
33f1c71d-2b05-8f12-87ea-5ce32bd83b97
46e5c81d-2b05-8f12-87ea-5ce32bd83b97
06a2c91d-2b05-8f12-87ea-5ce32bd83b97
651fca1d-2b05-8f12-87ea-5ce32bd83b97
b4bfcb1d-2b05-8f12-87ea-5ce32bd83b97
6ec0cc1d-2b05-8f12-87ea-5ce32bd83b97
ee7acd1d-2b05-8f12-87ea-5ce32bd83b97
38a0ce1d-2b05-8f12-87ea-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)

c0b1f6c7-16dc-4501-b85d-c7a2796e277c
9f2ec92d-384a-47fe-989f-cbcf3b16eff4
e20bcf94-bc95-42ad-b1d8-9ee4e2726605
6b377a9a-b0fe-4f9e-8026-a939a5e6d435
134918f5-7c5d-4070-abcf-14b9b727e1bb
d3dce2c3-5f31-4b9e-b5fc-f3cc3cd87f1d
458689bc-67ae-49c0-9bd0-72cd92c28a63
515369c5-2e13-4e1e-ae9f-eef06e0d743c
9277a47d-d289-4759-b1fb-2e27613a82f2
05a78879-05a0-4f44-a373-288f54cdd0c2
cf300a58-df16-451a-bc10-6f1d9acbd7cc
5598f188-1e3f-4f8a-9eaa-eedb78138194
6d0f0185-a066-4720-a7cb-b314d5693354
9bc2bd53-d622-493c-80b8-930525a89f35
fde385ac-fed0-4641-a2aa-9d647370d315

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: