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)

01a0a553-6d85-7c90-abb0-07f4fb031129
01a0a553-6d85-7e52-8c4d-ae21a42a0c0f
01a0a553-6d85-7f92-a2dc-1794cc76b179
01a0a553-6d86-70b1-92a4-24222916c7ca
01a0a553-6d86-71c7-9fb4-524ef3ab94c8
01a0a553-6d86-72de-9d73-c3cc6975f79b
01a0a553-6d86-73f0-a08f-964db558ea44
01a0a553-6d86-7507-9eae-a26c9a3e919c
01a0a553-6d86-761d-a634-7b86d7b8396d
01a0a553-6d86-7734-b6e8-f9fca8381854
01a0a553-6d86-784a-a82f-b44b03622d28
01a0a553-6d86-795d-ab69-f17ae2fb34d1
01a0a553-6d86-7a73-b134-cba725bfb6bf
01a0a553-6d86-7b86-9015-5cb908b1790e
01a0a553-6d86-7c98-9318-d93623e506fe

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)

1f1b10c1-e67a-672c-85c3-4cf95d479851
1f1b10c1-e67a-68ee-85c3-4cf95d479851
1f1b10c1-e67a-69f2-85c3-4cf95d479851
1f1b10c1-e67a-6ace-85c3-4cf95d479851
1f1b10c1-e67a-6b96-85c3-4cf95d479851
1f1b10c1-e67a-6c5e-85c3-4cf95d479851
1f1b10c1-e67a-6d26-85c3-4cf95d479851
1f1b10c1-e67a-6de4-85c3-4cf95d479851
1f1b10c1-e67a-6eac-85c3-4cf95d479851
1f1b10c1-e67a-6f74-85c3-4cf95d479851
1f1b10c1-e67b-60b4-85c3-4cf95d479851
1f1b10c1-e67b-6186-85c3-4cf95d479851
1f1b10c1-e67b-624e-85c3-4cf95d479851
1f1b10c1-e67b-630c-85c3-4cf95d479851
1f1b10c1-e67b-63d4-85c3-4cf95d479851

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)

1e67b4b0-b10c-11f1-85c3-4cf95d479851
1e67b514-b10c-11f1-85c3-4cf95d479851
1e67b582-b10c-11f1-85c3-4cf95d479851
1e67b5e6-b10c-11f1-85c3-4cf95d479851
1e67b640-b10c-11f1-85c3-4cf95d479851
1e67b6a4-b10c-11f1-85c3-4cf95d479851
1e67b708-b10c-11f1-85c3-4cf95d479851
1e67b76c-b10c-11f1-85c3-4cf95d479851
1e67b7d0-b10c-11f1-85c3-4cf95d479851
1e67b834-b10c-11f1-85c3-4cf95d479851
1e67b898-b10c-11f1-85c3-4cf95d479851
1e67b8f2-b10c-11f1-85c3-4cf95d479851
1e67b956-b10c-11f1-85c3-4cf95d479851
1e67b9b0-b10c-11f1-85c3-4cf95d479851
1e67ba0a-b10c-11f1-85c3-4cf95d479851

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)

a21e4d17-3d03-8210-87ea-5ce32bd83b97
fc324e17-3d03-8210-87ea-5ce32bd83b97
05844f17-3d03-8210-87ea-5ce32bd83b97
f0045017-3d03-8210-87ea-5ce32bd83b97
b8fb5117-3d03-8210-87ea-5ce32bd83b97
44e55217-3d03-8210-87ea-5ce32bd83b97
141b5317-3d03-8210-87ea-5ce32bd83b97
1bde5517-3d03-8210-87ea-5ce32bd83b97
33d95617-3d03-8210-87ea-5ce32bd83b97
0dde5717-3d03-8210-87ea-5ce32bd83b97
db675817-3d03-8210-87ea-5ce32bd83b97
f07d5917-3d03-8210-87ea-5ce32bd83b97
f8305a17-3d03-8210-87ea-5ce32bd83b97
7d725b17-3d03-8210-87ea-5ce32bd83b97
7dd05c17-3d03-8210-87ea-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)

c5bce118-3648-47c2-87d6-c51f501a21f7
e933ceca-792a-4cd3-8d9a-4972503d5e56
10fd20b7-f1a5-447f-8810-9e6a364b261a
c4261015-c4e7-49d9-8f66-fad1fa7258b0
fe40c075-4960-4c4a-a1fa-9665fad38f13
5eae7a64-65b0-4e0e-a208-ff015d43de8a
7b28e1e5-e141-4862-98ca-1cfc1b13b5af
9b51cbc8-a876-4531-9c05-423453257844
699b5b64-d2e9-43a8-8267-a14d6beb2347
2475710a-a932-4ca8-bb3d-8b58289c1eaf
25beafe9-fba4-46f5-8504-2829d4959501
42fbb101-5821-4c45-aa27-4a3103aade82
3d122380-ec36-4f8f-be60-d4a0a4d80521
a1d88d71-238d-4fdc-ad35-78a9a5fabbca
86b61c65-0a72-44bf-8c34-b323d0bbe6d0

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: