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)

01a1aa5d-98e9-747b-8424-87e36a57bf9f
01a1aa5d-98e9-767b-854c-3a677e33c965
01a1aa5d-98e9-77bb-b5a6-da1a96b849af
01a1aa5d-98e9-78da-a83f-2773a2cf3188
01a1aa5d-98e9-79f4-89f6-303f81776032
01a1aa5d-98e9-7b0b-be77-2684c2064caf
01a1aa5d-98e9-7c25-a13c-0417246edf85
01a1aa5d-98e9-7d3c-a1d6-a3961edeef4f
01a1aa5d-98e9-7e5f-9d1d-a7a06117b021
01a1aa5d-98e9-7f75-9932-08ddebac1384
01a1aa5d-98ea-708c-bdc0-c6132ed85c66
01a1aa5d-98ea-71a6-8695-46e072253431
01a1aa5d-98ea-72bd-8351-d19c2fc39dd9
01a1aa5d-98ea-73d3-8159-4b2a2d020bad
01a1aa5d-98ea-74ea-990f-4ef2e83f6041

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)

1f1d8e0f-ba68-6742-8703-4cf95d479851
1f1d8e0f-ba68-6922-8703-4cf95d479851
1f1d8e0f-ba68-6a12-8703-4cf95d479851
1f1d8e0f-ba68-6aee-8703-4cf95d479851
1f1d8e0f-ba68-6bb6-8703-4cf95d479851
1f1d8e0f-ba68-6c7e-8703-4cf95d479851
1f1d8e0f-ba68-6d50-8703-4cf95d479851
1f1d8e0f-ba68-6e0e-8703-4cf95d479851
1f1d8e0f-ba68-6ee0-8703-4cf95d479851
1f1d8e0f-ba68-6f9e-8703-4cf95d479851
1f1d8e0f-ba69-611a-8703-4cf95d479851
1f1d8e0f-ba69-61f6-8703-4cf95d479851
1f1d8e0f-ba69-62be-8703-4cf95d479851
1f1d8e0f-ba69-6386-8703-4cf95d479851
1f1d8e0f-ba69-6458-8703-4cf95d479851

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)

fba69534-d8e0-11f1-8703-4cf95d479851
fba69598-d8e0-11f1-8703-4cf95d479851
fba69610-d8e0-11f1-8703-4cf95d479851
fba69674-d8e0-11f1-8703-4cf95d479851
fba696d8-d8e0-11f1-8703-4cf95d479851
fba6973c-d8e0-11f1-8703-4cf95d479851
fba697aa-d8e0-11f1-8703-4cf95d479851
fba69804-d8e0-11f1-8703-4cf95d479851
fba69868-d8e0-11f1-8703-4cf95d479851
fba698c2-d8e0-11f1-8703-4cf95d479851
fba6991c-d8e0-11f1-8703-4cf95d479851
fba69976-d8e0-11f1-8703-4cf95d479851
fba699d0-d8e0-11f1-8703-4cf95d479851
fba69a2a-d8e0-11f1-8703-4cf95d479851
fba69a84-d8e0-11f1-8703-4cf95d479851

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)

a9fc2617-7d01-8513-87ea-5ce32bd83b97
598c2717-7d01-8513-87ea-5ce32bd83b97
2de12817-7d01-8513-87ea-5ce32bd83b97
1e3e2917-7d01-8513-87ea-5ce32bd83b97
943b2a17-7d01-8513-87ea-5ce32bd83b97
c55d2b17-7d01-8513-87ea-5ce32bd83b97
50842c17-7d01-8513-87ea-5ce32bd83b97
78d32d17-7d01-8513-87ea-5ce32bd83b97
94f92e17-7d01-8513-87ea-5ce32bd83b97
88952f17-7d01-8513-87ea-5ce32bd83b97
68c73017-7d01-8513-87ea-5ce32bd83b97
35773117-7d01-8513-87ea-5ce32bd83b97
eb7a3217-7d01-8513-87ea-5ce32bd83b97
54313317-7d01-8513-87ea-5ce32bd83b97
2e0b3417-7d01-8513-87ea-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)

0476467a-4d83-4d96-b3df-beded0946696
dba2896a-0c9c-4355-ae2a-e364015f1bd6
18f13340-3aee-4c94-a4dc-43c6db7cd5e8
0a494681-0839-4fbe-83fa-8cd7c5aa8e91
d78825c9-ff6c-4491-98b0-9b3acdf94685
397473bf-0d12-41eb-a3d8-4eb835bad184
79e10651-2fb8-4deb-918b-82fd5d086c14
457e1c9c-0c79-41c7-9e22-f4dbed174049
829a8ef4-5416-47e8-bb83-8aa53cb60d0c
35c54ff7-2a16-4be5-a0e4-6202b50911da
f9743994-326c-4b1c-86bf-39444c64e324
7e84bc23-6347-4119-bc0f-ff60fe6bb95f
36e5381f-f8df-4f57-9bf9-ec07f93eb9f7
ebb337f8-43ed-471f-afa2-730f1b9cfca0
e771dd32-c248-417e-8380-85950a640b1a

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: