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)

01a15472-d1fb-70c5-aace-3116c917485b
01a15472-d1fb-726b-9753-0eb601439837
01a15472-d1fb-7409-9c6b-71506a5fdd30
01a15472-d1fb-7561-92c4-3e58cc817291
01a15472-d1fb-767f-840e-c108ee9029e2
01a15472-d1fb-7796-be67-76ed6d0f630b
01a15472-d1fb-78ad-9934-0c7ebfaaae6b
01a15472-d1fb-79bf-8631-9cc29a99fddc
01a15472-d1fb-7ad5-8851-2ecc4dd77bfe
01a15472-d1fb-7bec-88e3-65df17a5020c
01a15472-d1fb-7cfe-a256-64ceda494f47
01a15472-d1fb-7e15-9f1a-b0a51843b803
01a15472-d1fb-7f2c-b6ff-6d4d4466eaf9
01a15472-d1fc-7046-8e2b-02f6e5c17898
01a15472-d1fc-7159-b4c7-9df667f10c2b

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)

1f1cbc4d-8abc-6b40-9e7c-4cf95d479851
1f1cbc4d-8abc-6d0c-9e7c-4cf95d479851
1f1cbc4d-8abc-6de8-9e7c-4cf95d479851
1f1cbc4d-8abc-6eba-9e7c-4cf95d479851
1f1cbc4d-8abc-6f78-9e7c-4cf95d479851
1f1cbc4d-8abd-6036-9e7c-4cf95d479851
1f1cbc4d-8abd-60f4-9e7c-4cf95d479851
1f1cbc4d-8abd-61b2-9e7c-4cf95d479851
1f1cbc4d-8abd-6270-9e7c-4cf95d479851
1f1cbc4d-8abd-632e-9e7c-4cf95d479851
1f1cbc4d-8abd-646e-9e7c-4cf95d479851
1f1cbc4d-8abd-6536-9e7c-4cf95d479851
1f1cbc4d-8abd-65f4-9e7c-4cf95d479851
1f1cbc4d-8abd-66a8-9e7c-4cf95d479851
1f1cbc4d-8abd-6766-9e7c-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)

d8abd838-cbc4-11f1-9e7c-4cf95d479851
d8abd89c-cbc4-11f1-9e7c-4cf95d479851
d8abd90a-cbc4-11f1-9e7c-4cf95d479851
d8abd964-cbc4-11f1-9e7c-4cf95d479851
d8abd9c8-cbc4-11f1-9e7c-4cf95d479851
d8abda22-cbc4-11f1-9e7c-4cf95d479851
d8abda7c-cbc4-11f1-9e7c-4cf95d479851
d8abdad6-cbc4-11f1-9e7c-4cf95d479851
d8abdb30-cbc4-11f1-9e7c-4cf95d479851
d8abdb9e-cbc4-11f1-9e7c-4cf95d479851
d8abdbf8-cbc4-11f1-9e7c-4cf95d479851
d8abdc5c-cbc4-11f1-9e7c-4cf95d479851
d8abdcc0-cbc4-11f1-9e7c-4cf95d479851
d8abdd1a-cbc4-11f1-9e7c-4cf95d479851
d8abdd7e-cbc4-11f1-9e7c-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)

22606f0d-4503-8412-87ea-5ce32bd83b97
83b2700d-4503-8412-87ea-5ce32bd83b97
a1df710d-4503-8412-87ea-5ce32bd83b97
4d3c730d-4503-8412-87ea-5ce32bd83b97
a3f0740d-4503-8412-87ea-5ce32bd83b97
a3d6750d-4503-8412-87ea-5ce32bd83b97
68ca760d-4503-8412-87ea-5ce32bd83b97
4acc770d-4503-8412-87ea-5ce32bd83b97
5133780d-4503-8412-87ea-5ce32bd83b97
009a790d-4503-8412-87ea-5ce32bd83b97
a87f7a0d-4503-8412-87ea-5ce32bd83b97
ea987b0d-4503-8412-87ea-5ce32bd83b97
17697c0d-4503-8412-87ea-5ce32bd83b97
85707d0d-4503-8412-87ea-5ce32bd83b97
4a147e0d-4503-8412-87ea-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)

26312790-c541-4f31-83db-7ad65f2eb3ee
d9c33874-b3e5-452f-ac5e-2e81960f2960
40605a88-264a-45b4-a7ed-9ce71a62b4eb
803c2897-83be-4136-9e74-c07e03dcc341
4daf6307-3257-4656-94ee-9ac6e983aef0
73c8e539-e292-4851-b30b-f1df4d915a85
095096b3-1824-404e-8112-358e5ba00577
132998e8-27d3-4680-a001-42d082e2491e
7150c828-2613-4ca1-9f7b-97be641e7ec9
e8a5d9a1-5a5c-49bd-8d21-30fc922cfed6
a5c6bf4b-25f7-46d1-94dc-d0d145e6107f
e6a47fe0-0add-4a27-b036-ad4969db7de3
3bf61887-7cec-4b16-9b12-ebd99bc5b7e7
df8804ce-6338-4ed4-b00b-cf15b703a75e
47f18884-ac42-492c-89ee-f0e5cff21f8b

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: