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)

019c79b5-7ec8-7a0d-934d-b81a6b9af830
019c79b5-7ec8-7be8-b62b-391828eb5845
019c79b5-7ec8-7d54-974a-2076a9aefe95
019c79b5-7ec8-7ea0-b451-4c910f980b8d
019c79b5-7ec8-7fe4-814a-f5758ed2dffc
019c79b5-7ec9-7123-8bd2-5449994c584a
019c79b5-7ec9-7267-b002-76643c0e4944
019c79b5-7ec9-73a6-9f00-94b9fca04141
019c79b5-7ec9-74e6-847b-fc1442bbe6c4
019c79b5-7ec9-7625-8f35-51363e8610bd
019c79b5-7ec9-7769-9d1a-430ccd3813d2
019c79b5-7ec9-78a8-9c27-5e1c0cc2527c
019c79b5-7ec9-79e4-bab8-d4b44ceb82f9
019c79b5-7ec9-7b23-a3f4-04ffbd1f8b24
019c79b5-7ec9-7c5f-a2cc-d29f5228831a

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)

1f10e245-529e-6e72-a500-4cf95d479851
1f10e245-529f-60de-a500-4cf95d479851
1f10e245-529f-626e-a500-4cf95d479851
1f10e245-529f-63ea-a500-4cf95d479851
1f10e245-529f-655c-a500-4cf95d479851
1f10e245-529f-66c4-a500-4cf95d479851
1f10e245-529f-682c-a500-4cf95d479851
1f10e245-529f-6994-a500-4cf95d479851
1f10e245-529f-6af2-a500-4cf95d479851
1f10e245-529f-6c5a-a500-4cf95d479851
1f10e245-529f-6e62-a500-4cf95d479851
1f10e245-529f-6fd4-a500-4cf95d479851
1f10e245-52a0-613c-a500-4cf95d479851
1f10e245-52a0-62a4-a500-4cf95d479851
1f10e245-52a0-6402-a500-4cf95d479851

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)

5e3475af-8206-451e-b752-513147ff670f
137c2962-02b0-49f8-af27-ced1e637ea84
8a6811dd-8b5c-4a06-8d27-f2a29d02e1d2
9e8d85b1-42a8-473f-b367-d66ff00f22d0
f275f154-13f7-4445-96c2-915c26675f2f
aca8dcfc-5b9f-4ea5-a737-359d89845012
c2396afc-c2fe-4075-a8f0-26e074a03d1b
1fed0b87-c786-4d97-bc49-b84bb92a9993
9dc8f653-ccd6-4232-bace-850dc7786775
5032d433-2b2e-4745-bea4-96b2018d73f1
24876b22-6bfb-4e01-a945-cb439639c1fd
de938877-4f73-494e-8c9b-2bfc536b96a3
949edd26-53ba-4cdd-a7f2-1dcbe66faacf
6f785fa1-187c-495f-8cdf-6d6ff1d6df52
ee42add2-7c53-4efa-95e4-9e92af3f71a5

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)

552a0d12-0e24-11f1-a500-4cf95d479851
552a0db2-0e24-11f1-a500-4cf95d479851
552a0e52-0e24-11f1-a500-4cf95d479851
552a0ef2-0e24-11f1-a500-4cf95d479851
552a0f88-0e24-11f1-a500-4cf95d479851
552a1028-0e24-11f1-a500-4cf95d479851
552a10c8-0e24-11f1-a500-4cf95d479851
552a115e-0e24-11f1-a500-4cf95d479851
552a11f4-0e24-11f1-a500-4cf95d479851
552a1294-0e24-11f1-a500-4cf95d479851
552a132a-0e24-11f1-a500-4cf95d479851
552a13b6-0e24-11f1-a500-4cf95d479851
552a1456-0e24-11f1-a500-4cf95d479851
552a14ec-0e24-11f1-a500-4cf95d479851
552a1582-0e24-11f1-a500-4cf95d479851

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)

ed0d9003-7e01-8303-87ea-5ce32bd83b97
424b9103-7e01-8303-87ea-5ce32bd83b97
876a9203-7e01-8303-87ea-5ce32bd83b97
55cd9303-7e01-8303-87ea-5ce32bd83b97
8a0a9403-7e01-8303-87ea-5ce32bd83b97
bddb9503-7e01-8303-87ea-5ce32bd83b97
46919603-7e01-8303-87ea-5ce32bd83b97
61b39703-7e01-8303-87ea-5ce32bd83b97
72d79803-7e01-8303-87ea-5ce32bd83b97
c4f89903-7e01-8303-87ea-5ce32bd83b97
cf129a03-7e01-8303-87ea-5ce32bd83b97
955d9b03-7e01-8303-87ea-5ce32bd83b97
c0499c03-7e01-8303-87ea-5ce32bd83b97
d1ec9d03-7e01-8303-87ea-5ce32bd83b97
33009e03-7e01-8303-87ea-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: