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)

018f1b4b-e36c-7baa-8cd8-6e9d0f19fc71
018f1b4b-e36c-7d75-bea5-15f43ea177cf
018f1b4b-e36c-7ebd-a0f6-4f16161f617c
018f1b4b-e36c-7fe0-ab70-0d78fa1e8e1a
018f1b4b-e36d-7077-b571-215fdc62ab0a
018f1b4b-e36d-7196-82b0-e9f6f49aec1e
018f1b4b-e36d-72b1-9ca6-4be46145466c
018f1b4b-e36d-7425-9981-d37d7ba232cf
018f1b4b-e36d-757d-a58e-13e69c06219c
018f1b4b-e36d-76a0-94e5-0c2a3f1647bb
018f1b4b-e36d-77bb-9bf5-a136da42751a
018f1b4b-e36d-78da-95b5-72b8e8a0311a
018f1b4b-e36d-79f0-ada3-0478f66e8fc7
018f1b4b-e36d-7b0b-8f1b-211cb0712cad
018f1b4b-e36d-7c25-959c-929e609ddfab

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)

1ef03ec5-7e53-63cc-8da4-4cf95d479851
1ef03ec5-7e53-6598-8da4-4cf95d479851
1ef03ec5-7e53-667e-8da4-4cf95d479851
1ef03ec5-7e53-675a-8da4-4cf95d479851
1ef03ec5-7e53-682c-8da4-4cf95d479851
1ef03ec5-7e53-68f4-8da4-4cf95d479851
1ef03ec5-7e53-69b2-8da4-4cf95d479851
1ef03ec5-7e53-6a84-8da4-4cf95d479851
1ef03ec5-7e53-6b42-8da4-4cf95d479851
1ef03ec5-7e53-6c0a-8da4-4cf95d479851
1ef03ec5-7e53-6d68-8da4-4cf95d479851
1ef03ec5-7e53-6e3a-8da4-4cf95d479851
1ef03ec5-7e53-6ef8-8da4-4cf95d479851
1ef03ec5-7e53-6fc0-8da4-4cf95d479851
1ef03ec5-7e54-607e-8da4-4cf95d479851

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)

6fd949c5-ad41-43e2-adbc-7313e822476a
d7685b64-e604-42fa-97e5-b8d89f4b9bc6
41ad05a6-8d3c-448b-8676-b514116cd771
bb0dd1e5-ca4d-45ea-8fea-1fcb365420c0
249cfccc-84da-4fca-a443-07991a6f9c6b
0b117261-17e2-40ad-8f0c-a811ee082148
2a82e986-c862-4e83-9ee6-a60396461a07
40a1e58e-7193-41d4-b56d-88eb4c24aeca
9e4f1ab4-758a-4889-be61-d3ec875a1355
aaef0121-ad73-4b1d-834d-0b307d28e7ea
cd5ef627-79a9-4a23-87f7-059b13beeffe
1628e533-cb6e-4f84-8e41-8d6a2eb5f077
1a81292d-6b18-4760-83a8-f1037b79e379
7612e5c1-42a9-4eca-b7e5-44a7bbe76cce
02deb655-2b72-4fcb-b733-fc5a7a553124

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)

57e545ba-03ec-11ef-8da4-4cf95d479851
57e54628-03ec-11ef-8da4-4cf95d479851
57e5468c-03ec-11ef-8da4-4cf95d479851
57e546f0-03ec-11ef-8da4-4cf95d479851
57e5475e-03ec-11ef-8da4-4cf95d479851
57e547c2-03ec-11ef-8da4-4cf95d479851
57e5483a-03ec-11ef-8da4-4cf95d479851
57e5489e-03ec-11ef-8da4-4cf95d479851
57e54902-03ec-11ef-8da4-4cf95d479851
57e54966-03ec-11ef-8da4-4cf95d479851
57e549ca-03ec-11ef-8da4-4cf95d479851
57e54a2e-03ec-11ef-8da4-4cf95d479851
57e54a9c-03ec-11ef-8da4-4cf95d479851
57e54b00-03ec-11ef-8da4-4cf95d479851
57e54b6e-03ec-11ef-8da4-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

6e9f5b09-03ee-8075-87e8-5ce32bd83b96
fce15c09-03ee-8075-87e8-5ce32bd83b96
adb85d09-03ee-8075-87e8-5ce32bd83b96
7b8c5e09-03ee-8075-87e8-5ce32bd83b96
c2d46009-03ee-8075-87e8-5ce32bd83b96
f8526109-03ee-8075-87e8-5ce32bd83b96
cea06209-03ee-8075-87e8-5ce32bd83b96
ae1f6309-03ee-8075-87e8-5ce32bd83b96
9d736409-03ee-8075-87e8-5ce32bd83b96
2d176509-03ee-8075-87e8-5ce32bd83b96
59706609-03ee-8075-87e8-5ce32bd83b96
836c6709-03ee-8075-87e8-5ce32bd83b96
2ca66809-03ee-8075-87e8-5ce32bd83b96
eda36909-03ee-8075-87e8-5ce32bd83b96
b4016a09-03ee-8075-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: