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)

01a1dabb-680b-7e4e-a547-48febfc2a91e
01a1dabb-680c-7057-b21f-40ccae48d81e
01a1dabb-680c-71e8-ae1c-f67055baa5b2
01a1dabb-680c-733c-903a-235f8012e550
01a1dabb-680c-747b-9b81-049ed044f297
01a1dabb-680c-75b3-977b-4c6a34e5f8f5
01a1dabb-680c-76f2-9c4e-726052f78b15
01a1dabb-680c-7846-a391-70f1de629f12
01a1dabb-680c-7992-a85c-508f0951996b
01a1dabb-680c-7acd-ac03-e6dde896b592
01a1dabb-680c-7c05-8d5f-893adcb6f102
01a1dabb-680c-7d3c-8989-81e7634b3f3a
01a1dabb-680c-7e88-bf52-5563155b5f3d
01a1dabb-680c-7fd3-b3dd-9847cd7af04c
01a1dabb-680d-710f-92cd-e07d6da32ffb

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)

1f1e0424-c11c-6396-b8a3-4cf95d479851
1f1e0424-c11c-672e-b8a3-4cf95d479851
1f1e0424-c11c-68d2-b8a3-4cf95d479851
1f1e0424-c11c-6a58-b8a3-4cf95d479851
1f1e0424-c11c-6bca-b8a3-4cf95d479851
1f1e0424-c11c-6d50-b8a3-4cf95d479851
1f1e0424-c11c-6eb8-b8a3-4cf95d479851
1f1e0424-c11d-603e-b8a3-4cf95d479851
1f1e0424-c11d-61b0-b8a3-4cf95d479851
1f1e0424-c11d-630e-b8a3-4cf95d479851
1f1e0424-c11d-6548-b8a3-4cf95d479851
1f1e0424-c11d-66ba-b8a3-4cf95d479851
1f1e0424-c11d-680e-b8a3-4cf95d479851
1f1e0424-c11d-696c-b8a3-4cf95d479851
1f1e0424-c11d-6ac0-b8a3-4cf95d479851

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)

4c11dc3c-e042-11f1-b8a3-4cf95d479851
4c11dcd2-e042-11f1-b8a3-4cf95d479851
4c11dd72-e042-11f1-b8a3-4cf95d479851
4c11ddfe-e042-11f1-b8a3-4cf95d479851
4c11de8a-e042-11f1-b8a3-4cf95d479851
4c11df2a-e042-11f1-b8a3-4cf95d479851
4c11dfc0-e042-11f1-b8a3-4cf95d479851
4c11e056-e042-11f1-b8a3-4cf95d479851
4c11e0f6-e042-11f1-b8a3-4cf95d479851
4c11e18c-e042-11f1-b8a3-4cf95d479851
4c11e236-e042-11f1-b8a3-4cf95d479851
4c11e2ea-e042-11f1-b8a3-4cf95d479851
4c11e38a-e042-11f1-b8a3-4cf95d479851
4c11e42a-e042-11f1-b8a3-4cf95d479851
4c11e4ca-e042-11f1-b8a3-4cf95d479851

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)

4d636425-b103-8e13-87ea-5ce32bd83b97
53486525-b103-8e13-87ea-5ce32bd83b97
cee26625-b103-8e13-87ea-5ce32bd83b97
08606725-b103-8e13-87ea-5ce32bd83b97
70c46825-b103-8e13-87ea-5ce32bd83b97
7b216925-b103-8e13-87ea-5ce32bd83b97
de606a25-b103-8e13-87ea-5ce32bd83b97
27e36b25-b103-8e13-87ea-5ce32bd83b97
51136c25-b103-8e13-87ea-5ce32bd83b97
447c6d25-b103-8e13-87ea-5ce32bd83b97
96076e25-b103-8e13-87ea-5ce32bd83b97
e73a6f25-b103-8e13-87ea-5ce32bd83b97
35d17025-b103-8e13-87ea-5ce32bd83b97
4cc47125-b103-8e13-87ea-5ce32bd83b97
6a567225-b103-8e13-87ea-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)

73745bff-b47f-47b5-bcb9-3e5d47967a3f
8fe5c285-072c-4720-b95e-28aca7c9b94e
8d36f37e-311b-43c4-9f31-1715eef5e4c0
b99e7a14-b026-42b9-953f-211056e8f04c
a02fe674-bb6d-4736-8f2c-a4b0f9cf22e3
7ab87a8c-d95f-44fc-bd48-2760133b6198
37c66324-48d8-4c43-8dda-88348f0c794d
bbf71e90-2f4e-4d88-99be-8e3b8b7fba60
bceabbc7-ebed-47e8-94ad-628d423b358e
a75fde48-5c58-4e08-b550-463dd602b509
0fb5ff2a-63df-40f0-bd85-7ea3411c6c2a
1cbf3113-3872-4878-b73c-16b790605908
d143a28d-cc69-4277-95ae-cf5adf54a139
89e98f56-8569-4d21-b76e-08c67d59513d
c9a64a66-a562-4c07-afb7-b091fccbc51d

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: