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)

019dc6c1-415f-706f-b76c-02d7e9ae801f
019dc6c1-4160-720d-aef3-6e334fec6e37
019dc6c1-4160-7350-86ca-b4c668bed2ae
019dc6c1-4160-7473-9d4b-26fcceacf87a
019dc6c1-4160-758e-8122-ed47fd013881
019dc6c1-4160-76a8-9424-911f12220af1
019dc6c1-4160-77c3-8aa6-6454cab00fd5
019dc6c1-4160-78de-a156-7161fbd2eb2e
019dc6c1-4160-7a3a-8228-8ef696be4739
019dc6c1-4160-7b54-b886-f94f0e3dbe35
019dc6c1-4160-7c6f-bbf1-c4134a2e3792
019dc6c1-4160-7d8a-87d6-c3f92db9eb1b
019dc6c1-4160-7ea4-ae6a-09e128a7c91d
019dc6c1-4160-7fbf-b95b-94383acdc0ae
019dc6c1-4161-70d5-9988-b62986921ae6

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)

1f140f5f-08b2-6440-87d4-4cf95d479851
1f140f5f-08b2-65c6-87d4-4cf95d479851
1f140f5f-08b2-66b6-87d4-4cf95d479851
1f140f5f-08b2-6788-87d4-4cf95d479851
1f140f5f-08b2-6850-87d4-4cf95d479851
1f140f5f-08b2-6918-87d4-4cf95d479851
1f140f5f-08b2-69d6-87d4-4cf95d479851
1f140f5f-08b2-6a94-87d4-4cf95d479851
1f140f5f-08b2-6b5c-87d4-4cf95d479851
1f140f5f-08b2-6c1a-87d4-4cf95d479851
1f140f5f-08b2-6d64-87d4-4cf95d479851
1f140f5f-08b2-6e40-87d4-4cf95d479851
1f140f5f-08b2-6ef4-87d4-4cf95d479851
1f140f5f-08b2-6fbc-87d4-4cf95d479851
1f140f5f-08b3-607a-87d4-4cf95d479851

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)

be2a2136-5bdd-4665-8f98-0f08b08802b6
19ed60ae-5537-4356-9fa9-df85f420c53f
1393458e-8243-404a-bb5c-f4427bde227d
58d423b2-1afb-4fc5-8fa6-a9a069c59d1c
b4f3d9e0-27a9-4fc9-9360-f93471fe0249
187c42f1-675b-4f0e-b8cd-070447a0ee3b
bb9de986-15d5-46b5-b21d-ce2f87028cc3
25a92947-8dcc-44e4-8993-cae9cede84ca
61cfc7cd-0819-4b42-a844-3dfa4490ec82
0e5c572d-b845-40a9-809f-2e45297a4bae
ee733132-6455-4bff-a82c-62ad75eaac5c
112b61eb-d334-4038-b0e2-0abd68521d9b
26a5b67e-d540-42c5-8d16-8ab408a50d22
c44e1ad4-e5ba-4edd-8039-20b68762f09b
f68eb8ee-cb59-4967-819f-c5adfd15be3b

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)

f08b358e-40f5-11f1-87d4-4cf95d479851
f08b35f2-40f5-11f1-87d4-4cf95d479851
f08b3656-40f5-11f1-87d4-4cf95d479851
f08b36b0-40f5-11f1-87d4-4cf95d479851
f08b3714-40f5-11f1-87d4-4cf95d479851
f08b376e-40f5-11f1-87d4-4cf95d479851
f08b37d2-40f5-11f1-87d4-4cf95d479851
f08b3836-40f5-11f1-87d4-4cf95d479851
f08b38a4-40f5-11f1-87d4-4cf95d479851
f08b3912-40f5-11f1-87d4-4cf95d479851
f08b3976-40f5-11f1-87d4-4cf95d479851
f08b39e4-40f5-11f1-87d4-4cf95d479851
f08b3a52-40f5-11f1-87d4-4cf95d479851
f08b3aac-40f5-11f1-87d4-4cf95d479851
f08b3b10-40f5-11f1-87d4-4cf95d479851

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)

a442331b-4405-8307-87ea-5ce32bd83b97
2e0b341b-4405-8307-87ea-5ce32bd83b97
7419361b-4405-8307-87ea-5ce32bd83b97
2bd2371b-4405-8307-87ea-5ce32bd83b97
9e8d381b-4405-8307-87ea-5ce32bd83b97
111d391b-4405-8307-87ea-5ce32bd83b97
52253a1b-4405-8307-87ea-5ce32bd83b97
71393b1b-4405-8307-87ea-5ce32bd83b97
03763c1b-4405-8307-87ea-5ce32bd83b97
139b3d1b-4405-8307-87ea-5ce32bd83b97
30a53e1b-4405-8307-87ea-5ce32bd83b97
59963f1b-4405-8307-87ea-5ce32bd83b97
8ac7401b-4405-8307-87ea-5ce32bd83b97
3a59411b-4405-8307-87ea-5ce32bd83b97
961c421b-4405-8307-87ea-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: