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)

019f206b-1d02-785f-b1a2-668840ea854e
019f206b-1d02-7a90-bb4d-953ef4c95fdc
019f206b-1d02-7bd3-9118-9fe42300e73d
019f206b-1d02-7cf2-8056-88723dbef980
019f206b-1d02-7e09-bb6f-82b54202dc1c
019f206b-1d02-7f1f-ab18-933c0250bc09
019f206b-1d03-7036-9beb-32dcd1026a8d
019f206b-1d03-714c-ad1a-074908da55ad
019f206b-1d03-7263-b4f2-025fafdbb98c
019f206b-1d03-7375-86c6-63f5829d9aaf
019f206b-1d03-7488-aa6e-3b475251a236
019f206b-1d03-759e-8936-3f6a8ab7eea3
019f206b-1d03-76b1-9740-9c8b0d51252b
019f206b-1d03-77c7-979a-1d2929113b2f
019f206b-1d03-7954-bbc9-5eab160179af

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)

1f175b46-b9ea-615a-b536-4cf95d479851
1f175b46-b9ea-636c-b536-4cf95d479851
1f175b46-b9ea-645c-b536-4cf95d479851
1f175b46-b9ea-652e-b536-4cf95d479851
1f175b46-b9ea-6600-b536-4cf95d479851
1f175b46-b9ea-66be-b536-4cf95d479851
1f175b46-b9ea-6786-b536-4cf95d479851
1f175b46-b9ea-6844-b536-4cf95d479851
1f175b46-b9ea-6902-b536-4cf95d479851
1f175b46-b9ea-69ca-b536-4cf95d479851
1f175b46-b9ea-6b32-b536-4cf95d479851
1f175b46-b9ea-6c04-b536-4cf95d479851
1f175b46-b9ea-6cc2-b536-4cf95d479851
1f175b46-b9ea-6d80-b536-4cf95d479851
1f175b46-b9ea-6e3e-b536-4cf95d479851

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)

6b9eaf24-75b4-11f1-b536-4cf95d479851
6b9eaf92-75b4-11f1-b536-4cf95d479851
6b9eb000-75b4-11f1-b536-4cf95d479851
6b9eb064-75b4-11f1-b536-4cf95d479851
6b9eb0c8-75b4-11f1-b536-4cf95d479851
6b9eb136-75b4-11f1-b536-4cf95d479851
6b9eb1a4-75b4-11f1-b536-4cf95d479851
6b9eb208-75b4-11f1-b536-4cf95d479851
6b9eb262-75b4-11f1-b536-4cf95d479851
6b9eb2bc-75b4-11f1-b536-4cf95d479851
6b9eb32a-75b4-11f1-b536-4cf95d479851
6b9eb384-75b4-11f1-b536-4cf95d479851
6b9eb3e8-75b4-11f1-b536-4cf95d479851
6b9eb456-75b4-11f1-b536-4cf95d479851
6b9eb4ba-75b4-11f1-b536-4cf95d479851

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)

7203883a-5200-870b-87ea-5ce32bd83b97
623d893a-5200-870b-87ea-5ce32bd83b97
5daf8a3a-5200-870b-87ea-5ce32bd83b97
425a8b3a-5200-870b-87ea-5ce32bd83b97
10428c3a-5200-870b-87ea-5ce32bd83b97
cab78d3a-5200-870b-87ea-5ce32bd83b97
ca168e3a-5200-870b-87ea-5ce32bd83b97
5f208f3a-5200-870b-87ea-5ce32bd83b97
6725903a-5200-870b-87ea-5ce32bd83b97
6d44913a-5200-870b-87ea-5ce32bd83b97
5482923a-5200-870b-87ea-5ce32bd83b97
1c25933a-5200-870b-87ea-5ce32bd83b97
c00b943a-5200-870b-87ea-5ce32bd83b97
8ea7953a-5200-870b-87ea-5ce32bd83b97
0c69963a-5200-870b-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)

2ee509a9-c44d-4703-8a1a-db1df5310796
95d4e79f-2fdb-45b2-b5e8-1befb88d737c
4b60c644-fbb9-4bcd-8a59-124daa0ca077
6fd9c1b0-8e45-4d9b-991c-f10f3390529b
d6249a53-8859-4aff-94de-af462b08d189
66e4ddf4-dbb5-43ff-a521-b39817c310ac
44be2844-24c5-44a9-9d9d-456b1a400bc3
d725501a-adcd-4c64-9fe7-5df12155d667
ba6804c9-c80f-418f-9d17-24d9a44b2fdb
18b3c76c-23a3-4aa2-b33c-255c65f36ef0
e574bd30-007e-471b-97d2-fabac534e510
db744402-e29d-4417-9a84-506e6600754d
e0409ff1-9c63-4eec-a679-2f6b91df679e
e9cf6b15-6bcc-41f8-94d8-b9c9c6b7e41c
340e5f58-4e1c-4793-93f6-a54c4a50c4fe

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: