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)

019fdef1-4cdd-7ab9-8200-367b625b214a
019fdef1-4cdd-7c7b-af7b-d90b5be4ca88
019fdef1-4cdd-7dbb-ae21-00c091a39313
019fdef1-4cdd-7ed1-a2a1-6fb50777c657
019fdef1-4cdd-7fe8-9efb-335a51cad0f7
019fdef1-4cde-70fa-82f9-14d052b35113
019fdef1-4cde-7211-8e15-0ff300d38ff9
019fdef1-4cde-7327-9e15-b6bb21ae05b6
019fdef1-4cde-743a-b697-c30d4bb3e5ea
019fdef1-4cde-754c-b0a5-84896a0c9f34
019fdef1-4cde-765f-b9f1-e9982775fcaf
019fdef1-4cde-7771-bc92-4b44345a9e1a
019fdef1-4cde-77f4-9aef-ad61adb0031b
019fdef1-4cde-790b-9ac0-43af58bf5be2
019fdef1-4cde-7a1d-8354-1bdce9e4b945

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)

1f192c6c-54d7-68f0-8b12-4cf95d479851
1f192c6c-54d7-6b02-8b12-4cf95d479851
1f192c6c-54d7-6bfc-8b12-4cf95d479851
1f192c6c-54d7-6cc4-8b12-4cf95d479851
1f192c6c-54d7-6d82-8b12-4cf95d479851
1f192c6c-54d7-6e4a-8b12-4cf95d479851
1f192c6c-54d7-6f08-8b12-4cf95d479851
1f192c6c-54d7-6fc6-8b12-4cf95d479851
1f192c6c-54d8-6084-8b12-4cf95d479851
1f192c6c-54d8-6142-8b12-4cf95d479851
1f192c6c-54d8-6282-8b12-4cf95d479851
1f192c6c-54d8-634a-8b12-4cf95d479851
1f192c6c-54d8-6408-8b12-4cf95d479851
1f192c6c-54d8-64c6-8b12-4cf95d479851
1f192c6c-54d8-6584-8b12-4cf95d479851

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)

c54d8656-92c6-11f1-8b12-4cf95d479851
c54d86c4-92c6-11f1-8b12-4cf95d479851
c54d871e-92c6-11f1-8b12-4cf95d479851
c54d878c-92c6-11f1-8b12-4cf95d479851
c54d87e6-92c6-11f1-8b12-4cf95d479851
c54d884a-92c6-11f1-8b12-4cf95d479851
c54d88ae-92c6-11f1-8b12-4cf95d479851
c54d8912-92c6-11f1-8b12-4cf95d479851
c54d8976-92c6-11f1-8b12-4cf95d479851
c54d89da-92c6-11f1-8b12-4cf95d479851
c54d8a3e-92c6-11f1-8b12-4cf95d479851
c54d8aa2-92c6-11f1-8b12-4cf95d479851
c54d8b06-92c6-11f1-8b12-4cf95d479851
c54d8b6a-92c6-11f1-8b12-4cf95d479851
c54d8bce-92c6-11f1-8b12-4cf95d479851

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)

6485a817-4d00-8c0d-87ea-5ce32bd83b97
22e8a917-4d00-8c0d-87ea-5ce32bd83b97
9f88aa17-4d00-8c0d-87ea-5ce32bd83b97
5df5ab17-4d00-8c0d-87ea-5ce32bd83b97
12b1ac17-4d00-8c0d-87ea-5ce32bd83b97
41c4ad17-4d00-8c0d-87ea-5ce32bd83b97
51cdae17-4d00-8c0d-87ea-5ce32bd83b97
4267af17-4d00-8c0d-87ea-5ce32bd83b97
9d95b017-4d00-8c0d-87ea-5ce32bd83b97
cc5bb117-4d00-8c0d-87ea-5ce32bd83b97
ee76b217-4d00-8c0d-87ea-5ce32bd83b97
9aa7b317-4d00-8c0d-87ea-5ce32bd83b97
7721b417-4d00-8c0d-87ea-5ce32bd83b97
762eb517-4d00-8c0d-87ea-5ce32bd83b97
d36ab617-4d00-8c0d-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)

c452bc1c-991e-41f6-8241-fbc04c215146
04390d4e-bc43-4e41-8c2a-b4beec9bcf9e
d9951ced-984f-41a7-a61b-bbf96d976d42
8bb078f3-9806-4d50-8f3f-d19d1d66d481
0a86a4f9-826a-46f5-a00b-844d9826610c
fc0d2099-40c7-4cb7-84c6-163532406d9b
e8139bdc-5a1e-4554-a1d2-a899e5b1479a
a6db3f3f-8482-45f7-b215-94c911664e53
a6c2f6d8-c7dc-40cd-8f33-5b8a7b19450c
0593b1a0-9ed2-4f63-a430-04c7430cc69d
f0b7d2f0-5294-4e2d-938d-fffcddbc3843
b411bc12-406e-4b5a-96ee-793241b0929f
5e2d0924-0c53-47d3-b4cc-55f5cb34da4b
1086b424-e291-4e36-afa4-b986b7bb453d
3061441a-ed76-4c77-a3b9-a464586a2417

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: