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)

019eaa35-72d8-7a6b-b74d-c692b08d7924
019eaa35-72d8-7c46-a1e0-9574f098ef18
019eaa35-72d8-7d86-a270-8de39eda44b7
019eaa35-72d8-7ea8-8b25-ea4a762d4743
019eaa35-72d8-7fbf-afc5-9eee16343d1c
019eaa35-72d9-70d1-b9c2-90fa1ca238d0
019eaa35-72d9-71ec-8230-530f654e91a0
019eaa35-72d9-7303-aba3-54485deaf181
019eaa35-72d9-7415-bc07-3641aa63a45a
019eaa35-72d9-752c-85fb-a17663ee5b90
019eaa35-72d9-763e-896d-2a372521ddae
019eaa35-72d9-7754-a911-6b9d118db0cf
019eaa35-72d9-7867-8ad7-ba2ab29d9344
019eaa35-72d9-7979-85d1-8effadf56389
019eaa35-72d9-7a8c-b225-aafd2b7f771c

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)

1f163aad-b579-6a86-9ae7-4cf95d479851
1f163aad-b579-6c3e-9ae7-4cf95d479851
1f163aad-b579-6d2e-9ae7-4cf95d479851
1f163aad-b579-6e0a-9ae7-4cf95d479851
1f163aad-b579-6ed2-9ae7-4cf95d479851
1f163aad-b579-6f9a-9ae7-4cf95d479851
1f163aad-b57a-606c-9ae7-4cf95d479851
1f163aad-b57a-6134-9ae7-4cf95d479851
1f163aad-b57a-61f2-9ae7-4cf95d479851
1f163aad-b57a-62c4-9ae7-4cf95d479851
1f163aad-b57a-640e-9ae7-4cf95d479851
1f163aad-b57a-64e0-9ae7-4cf95d479851
1f163aad-b57a-65b2-9ae7-4cf95d479851
1f163aad-b57a-6670-9ae7-4cf95d479851
1f163aad-b57a-6742-9ae7-4cf95d479851

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)

db57a828-63aa-11f1-9ae7-4cf95d479851
db57a896-63aa-11f1-9ae7-4cf95d479851
db57a8fa-63aa-11f1-9ae7-4cf95d479851
db57a968-63aa-11f1-9ae7-4cf95d479851
db57a9cc-63aa-11f1-9ae7-4cf95d479851
db57aa26-63aa-11f1-9ae7-4cf95d479851
db57aa8a-63aa-11f1-9ae7-4cf95d479851
db57aae4-63aa-11f1-9ae7-4cf95d479851
db57ab48-63aa-11f1-9ae7-4cf95d479851
db57abb6-63aa-11f1-9ae7-4cf95d479851
db57ac1a-63aa-11f1-9ae7-4cf95d479851
db57ac74-63aa-11f1-9ae7-4cf95d479851
db57acce-63aa-11f1-9ae7-4cf95d479851
db57ad32-63aa-11f1-9ae7-4cf95d479851
db57ad8c-63aa-11f1-9ae7-4cf95d479851

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)

11e1130a-9500-800a-87ea-5ce32bd83b97
673c140a-9500-800a-87ea-5ce32bd83b97
ef68150a-9500-800a-87ea-5ce32bd83b97
cb50160a-9500-800a-87ea-5ce32bd83b97
3fbf170a-9500-800a-87ea-5ce32bd83b97
28d2180a-9500-800a-87ea-5ce32bd83b97
ffb7190a-9500-800a-87ea-5ce32bd83b97
947b1a0a-9500-800a-87ea-5ce32bd83b97
27771b0a-9500-800a-87ea-5ce32bd83b97
17d11c0a-9500-800a-87ea-5ce32bd83b97
af661d0a-9500-800a-87ea-5ce32bd83b97
fbe11e0a-9500-800a-87ea-5ce32bd83b97
586b1f0a-9500-800a-87ea-5ce32bd83b97
cc56200a-9500-800a-87ea-5ce32bd83b97
a42a210a-9500-800a-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)

a5329295-b80c-470d-a960-89d90eb754c6
cb8ac563-df29-4589-9dc3-a7041e607c16
b2159c7a-b6ce-4d46-8533-030f53f8da93
982c7218-0c80-4d09-a1a7-ab8e178b4b7b
da4e5f20-4b51-467c-a3f7-4fded96f4fa4
03c934b9-0a73-406c-9cb5-104a5289a113
5f3cf147-5011-4f54-8a0d-e1d6fa64213d
97086e26-c957-4b95-8592-9a2057f81bf0
945eef37-2b23-4fd8-a011-3d03752159ed
50c75537-41a8-465d-afbb-926f9f415ccc
5860535f-546d-4ca1-b125-6707b4fc76a4
92cf2da9-a6e3-4bd0-b154-7fc20c3ec5a4
e98c84b8-5141-452b-a5ad-fbde64eb3819
8c8081cd-657a-417e-b731-a37c0f1036fc
b483560a-ef6c-47ff-a159-f10a0c2a525c

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: