UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate random and/or time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate random (version 4) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) 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)

019bbf1d-5cc6-73cb-bc36-d4f33aeaba6a
019bbf1d-5cc6-7582-98a5-507b9a282efe
019bbf1d-5cc6-76c5-8221-150e93439315
019bbf1d-5cc6-77e8-9250-a2e845e5e3d8
019bbf1d-5cc6-78fe-94a4-bd499dbd9134
019bbf1d-5cc6-7a15-b4b8-73f086e4c0b6
019bbf1d-5cc6-7b2c-a509-d9ef2f3a2530
019bbf1d-5cc6-7c4a-8449-7b7123de53a6
019bbf1d-5cc6-7d61-98fc-16f57667f5bf
019bbf1d-5cc6-7e7b-9de7-9c19f4e8eb84
019bbf1d-5cc6-7f92-a268-ab02bcb6b467
019bbf1d-5cc7-70a8-ba36-f1e9a93ad6c6
019bbf1d-5cc7-71bf-9b74-3c8f961cd333
019bbf1d-5cc7-72d5-8780-71ec5c1f7701
019bbf1d-5cc7-73ec-a637-b67670390cd2

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)

1f0f1ab7-e796-6c52-a2c0-4cf95d479851
1f0f1ab7-e796-6df6-a2c0-4cf95d479851
1f0f1ab7-e796-6ee6-a2c0-4cf95d479851
1f0f1ab7-e796-6fb8-a2c0-4cf95d479851
1f0f1ab7-e797-608a-a2c0-4cf95d479851
1f0f1ab7-e797-6152-a2c0-4cf95d479851
1f0f1ab7-e797-621a-a2c0-4cf95d479851
1f0f1ab7-e797-62e2-a2c0-4cf95d479851
1f0f1ab7-e797-63aa-a2c0-4cf95d479851
1f0f1ab7-e797-6472-a2c0-4cf95d479851
1f0f1ab7-e797-65bc-a2c0-4cf95d479851
1f0f1ab7-e797-668e-a2c0-4cf95d479851
1f0f1ab7-e797-6756-a2c0-4cf95d479851
1f0f1ab7-e797-6814-a2c0-4cf95d479851
1f0f1ab7-e797-68dc-a2c0-4cf95d479851

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)

281cdb13-2e1c-40a4-95c9-bea54a2e4728
c3187194-83db-41ce-a695-cfae464e3e7c
9fa3a9ed-9574-4c41-a008-57bda5bc0968
a7179a07-c5a7-4051-9862-7031f612de10
e028f030-7202-4b36-9b83-2d4e3546386d
4fdb18d3-4b41-44fd-8d6b-10cc692a67cc
5061387a-e451-4e5e-a8e2-5b857c9f8a54
eb5a382b-3fd0-45f5-9f92-804b16e7cc9c
fd844d69-6426-4d15-9773-890c402849c4
8ad2319c-8661-4de2-a7ce-1e308d6f2ef0
28231f5e-00fc-48d1-9e6f-364c7fdb3c10
70e68842-542a-4eeb-94a2-8d33c38daac3
2ba4de2c-cbb6-49fe-82b8-b3a9b92e5f6a
3ed469e0-8670-48e0-816f-5565c391706e
781d651f-cf97-4232-8b2e-ddc9b8734a76

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)

7e797df0-f1ab-11f0-a2c0-4cf95d479851
7e797e54-f1ab-11f0-a2c0-4cf95d479851
7e797eb8-f1ab-11f0-a2c0-4cf95d479851
7e797f12-f1ab-11f0-a2c0-4cf95d479851
7e797f76-f1ab-11f0-a2c0-4cf95d479851
7e797fd0-f1ab-11f0-a2c0-4cf95d479851
7e798034-f1ab-11f0-a2c0-4cf95d479851
7e7980a2-f1ab-11f0-a2c0-4cf95d479851
7e7980fc-f1ab-11f0-a2c0-4cf95d479851
7e798156-f1ab-11f0-a2c0-4cf95d479851
7e7981c4-f1ab-11f0-a2c0-4cf95d479851
7e798228-f1ab-11f0-a2c0-4cf95d479851
7e798296-f1ab-11f0-a2c0-4cf95d479851
7e7982fa-f1ab-11f0-a2c0-4cf95d479851
7e79835e-f1ab-11f0-a2c0-4cf95d479851

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)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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)

0ede351f-2e00-8f00-87ea-5ce32bd83b97
8175361f-2e00-8f00-87ea-5ce32bd83b97
93e7371f-2e00-8f00-87ea-5ce32bd83b97
d88f381f-2e00-8f00-87ea-5ce32bd83b97
e1b0391f-2e00-8f00-87ea-5ce32bd83b97
d9bd3a1f-2e00-8f00-87ea-5ce32bd83b97
4aa33b1f-2e00-8f00-87ea-5ce32bd83b97
e2fb3c1f-2e00-8f00-87ea-5ce32bd83b97
7e223d1f-2e00-8f00-87ea-5ce32bd83b97
aa363e1f-2e00-8f00-87ea-5ce32bd83b97
5d973f1f-2e00-8f00-87ea-5ce32bd83b97
6e48401f-2e00-8f00-87ea-5ce32bd83b97
c409411f-2e00-8f00-87ea-5ce32bd83b97
032a431f-2e00-8f00-87ea-5ce32bd83b97
3dd4441f-2e00-8f00-87ea-5ce32bd83b97

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: