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)

019e8fa2-374c-7e7b-8669-7af815310a31
019e8fa2-374c-7000-8d4d-d9b8c981a113
019e8fa2-374d-7148-b24b-3ba6b72059b0
019e8fa2-374d-726b-a57e-ada8fde5cbf8
019e8fa2-374d-738a-ad5c-315944486f7d
019e8fa2-374d-74a8-b465-8efb3218fbb7
019e8fa2-374d-75c7-992d-d776a8087956
019e8fa2-374d-76e6-95f5-ed32ed9835bc
019e8fa2-374d-7805-a890-e7be22406f8d
019e8fa2-374d-7923-9b41-0e9693dffbc7
019e8fa2-374d-7a42-bcf5-20da2188617a
019e8fa2-374d-7b61-8dc2-1547b4bc7c41
019e8fa2-374d-7c7b-9aed-00129027ac5f
019e8fa2-374d-7d9a-9b42-b1392fe988d8
019e8fa2-374d-7eb9-a20c-6a284604e333

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)

1f15f9cc-4119-679e-b2eb-4cf95d479851
1f15f9cc-4119-6942-b2eb-4cf95d479851
1f15f9cc-4119-6a32-b2eb-4cf95d479851
1f15f9cc-4119-6b04-b2eb-4cf95d479851
1f15f9cc-4119-6bd6-b2eb-4cf95d479851
1f15f9cc-4119-6ca8-b2eb-4cf95d479851
1f15f9cc-4119-6d70-b2eb-4cf95d479851
1f15f9cc-4119-6e38-b2eb-4cf95d479851
1f15f9cc-4119-6f00-b2eb-4cf95d479851
1f15f9cc-4119-6fc8-b2eb-4cf95d479851
1f15f9cc-411a-6112-b2eb-4cf95d479851
1f15f9cc-411a-61ee-b2eb-4cf95d479851
1f15f9cc-411a-62c0-b2eb-4cf95d479851
1f15f9cc-411a-6388-b2eb-4cf95d479851
1f15f9cc-411a-645a-b2eb-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)

c411a536-5f9c-11f1-b2eb-4cf95d479851
c411a59a-5f9c-11f1-b2eb-4cf95d479851
c411a608-5f9c-11f1-b2eb-4cf95d479851
c411a66c-5f9c-11f1-b2eb-4cf95d479851
c411a6d0-5f9c-11f1-b2eb-4cf95d479851
c411a73e-5f9c-11f1-b2eb-4cf95d479851
c411a7ac-5f9c-11f1-b2eb-4cf95d479851
c411a806-5f9c-11f1-b2eb-4cf95d479851
c411a874-5f9c-11f1-b2eb-4cf95d479851
c411a8d8-5f9c-11f1-b2eb-4cf95d479851
c411a932-5f9c-11f1-b2eb-4cf95d479851
c411a996-5f9c-11f1-b2eb-4cf95d479851
c411ac02-5f9c-11f1-b2eb-4cf95d479851
c411acde-5f9c-11f1-b2eb-4cf95d479851
c411adba-5f9c-11f1-b2eb-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)

6f336c0d-4e05-8a09-87ea-5ce32bd83b97
1d8d6d0d-4e05-8a09-87ea-5ce32bd83b97
48db6e0d-4e05-8a09-87ea-5ce32bd83b97
47686f0d-4e05-8a09-87ea-5ce32bd83b97
e594700d-4e05-8a09-87ea-5ce32bd83b97
75fc710d-4e05-8a09-87ea-5ce32bd83b97
7aa6720d-4e05-8a09-87ea-5ce32bd83b97
f422730d-4e05-8a09-87ea-5ce32bd83b97
25e3740d-4e05-8a09-87ea-5ce32bd83b97
7e9d750d-4e05-8a09-87ea-5ce32bd83b97
7a9e760d-4e05-8a09-87ea-5ce32bd83b97
1de2770d-4e05-8a09-87ea-5ce32bd83b97
eb86780d-4e05-8a09-87ea-5ce32bd83b97
f3c2790d-4e05-8a09-87ea-5ce32bd83b97
33a07a0d-4e05-8a09-87ea-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)

d225abb0-7b84-4b72-b722-076ac473bea4
1f81fded-78e4-4029-8a84-431305b26018
4e683933-8049-4c72-9beb-8bbb6176f703
b5df78a0-2c6a-49bb-bc02-5b7368297c3c
422fb2c3-0eb7-4aac-82a6-f266d2131b6a
19fc4023-f39a-4a8c-bb6a-96f08d263425
559b1b20-12e5-40e2-a1f9-2d4f89316b5b
f44a6ef4-a281-4dc9-86a9-e8ccde73697a
9f17933c-501e-42c0-920c-9c2960541feb
9329f892-1d37-4225-b1c3-4e202990ae0a
69f66c6c-b935-4e76-9475-217f7f4cb877
9dd7cf5b-f830-4674-a765-64b229ce2406
f1c789c0-3120-4782-85f1-16cbb8359bba
174bdf71-d8b5-40ea-8c06-127effacb085
8e85850c-9216-4d31-bc1c-597c43d443e0

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: