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)

01a0e3a2-4510-7429-9099-2a9e9bcdb042
01a0e3a2-4510-75b7-92f0-b1cf32aeacce
01a0e3a2-4510-76f6-949f-fb32f3a731f6
01a0e3a2-4510-7811-b234-3db02d14371d
01a0e3a2-4510-7927-9caf-23d6ede85740
01a0e3a2-4510-7a3e-925c-7f930a893390
01a0e3a2-4510-7b54-8203-cff76a50a314
01a0e3a2-4510-7c6b-9ef0-107018b2fdc1
01a0e3a2-4510-7d82-973d-dffa1b72f0fb
01a0e3a2-4510-7e94-9f5a-5da74c5605a0
01a0e3a2-4510-7faa-9d9a-935b7592d80d
01a0e3a2-4511-70bd-b437-8b9da3306dda
01a0e3a2-4511-71d3-b4aa-c8e15551aacc
01a0e3a2-4511-72ea-ae26-f7fa6f2611bf
01a0e3a2-4511-73d8-9850-9ae7e5ae13a4

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)

1f1ba8e0-62b3-656c-8b24-4cf95d479851
1f1ba8e0-62b3-672e-8b24-4cf95d479851
1f1ba8e0-62b3-681e-8b24-4cf95d479851
1f1ba8e0-62b3-68f0-8b24-4cf95d479851
1f1ba8e0-62b3-69c2-8b24-4cf95d479851
1f1ba8e0-62b3-6a80-8b24-4cf95d479851
1f1ba8e0-62b3-6b48-8b24-4cf95d479851
1f1ba8e0-62b3-6c10-8b24-4cf95d479851
1f1ba8e0-62b3-6cd8-8b24-4cf95d479851
1f1ba8e0-62b3-6d96-8b24-4cf95d479851
1f1ba8e0-62b3-6eea-8b24-4cf95d479851
1f1ba8e0-62b3-6fbc-8b24-4cf95d479851
1f1ba8e0-62b4-607a-8b24-4cf95d479851
1f1ba8e0-62b4-6142-8b24-4cf95d479851
1f1ba8e0-62b4-6200-8b24-4cf95d479851

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)

062b42dc-ba8e-11f1-8b24-4cf95d479851
062b4340-ba8e-11f1-8b24-4cf95d479851
062b43a4-ba8e-11f1-8b24-4cf95d479851
062b43fe-ba8e-11f1-8b24-4cf95d479851
062b4458-ba8e-11f1-8b24-4cf95d479851
062b44bc-ba8e-11f1-8b24-4cf95d479851
062b4520-ba8e-11f1-8b24-4cf95d479851
062b4584-ba8e-11f1-8b24-4cf95d479851
062b45e8-ba8e-11f1-8b24-4cf95d479851
062b4656-ba8e-11f1-8b24-4cf95d479851
062b46ba-ba8e-11f1-8b24-4cf95d479851
062b4728-ba8e-11f1-8b24-4cf95d479851
062b478c-ba8e-11f1-8b24-4cf95d479851
062b47fa-ba8e-11f1-8b24-4cf95d479851
062b485e-ba8e-11f1-8b24-4cf95d479851

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)

e7cbae39-cb03-8e10-87ea-5ce32bd83b97
af46af39-cb03-8e10-87ea-5ce32bd83b97
b736b039-cb03-8e10-87ea-5ce32bd83b97
2772b139-cb03-8e10-87ea-5ce32bd83b97
f9c5b239-cb03-8e10-87ea-5ce32bd83b97
47dfb339-cb03-8e10-87ea-5ce32bd83b97
e9e7b439-cb03-8e10-87ea-5ce32bd83b97
1041b539-cb03-8e10-87ea-5ce32bd83b97
d3bab639-cb03-8e10-87ea-5ce32bd83b97
425eb739-cb03-8e10-87ea-5ce32bd83b97
26c6b839-cb03-8e10-87ea-5ce32bd83b97
5a92b939-cb03-8e10-87ea-5ce32bd83b97
193aba39-cb03-8e10-87ea-5ce32bd83b97
45bcbb39-cb03-8e10-87ea-5ce32bd83b97
b82cbc39-cb03-8e10-87ea-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)

91d4130c-d9c7-427f-8378-5b2493444f93
0a03ed1f-44b7-4838-83fb-ffdea9b0d82b
e9406df4-a6e1-44f7-a112-ebb8d5374f50
b6b4532f-667e-48ad-a116-efc30c768a21
0a32aaf0-ec91-4092-a855-932e3fd23002
0fe27ad8-2bd9-456a-b0f0-7ae53c31a044
2a9111fa-de9d-4c5e-aef2-1c1c93e8f216
67751709-9640-4b90-baeb-4a64c99b25cb
ce56a184-aad8-4a78-8120-6ad1266a8b0a
a9e09f63-c9cd-49ca-8562-c4700e6381cf
06e59251-3fc9-4959-b43b-4978307e6c47
565e556d-840e-47b1-9bc0-f4b806aae296
1d19e639-3fb6-47a3-9fd2-03601d17c644
31bfcde8-bf77-4056-a48a-60d0d7816eff
fb10c592-09d0-462f-82a8-50bfa5dc3366

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: