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)

01a10d7c-7802-7ec5-a005-c9563df7b0da
01a10d7c-7803-705b-b9be-b734ddf879fd
01a10d7c-7803-719a-be9b-65dba40b855f
01a10d7c-7803-72b1-98e0-e78b3a3d9129
01a10d7c-7803-73c3-a052-7b129386786a
01a10d7c-7803-74da-adf3-31634ff98da5
01a10d7c-7803-75ec-8b8c-6454763244f6
01a10d7c-7803-770b-8292-9532012513b9
01a10d7c-7803-781d-bc21-bc2f97742e71
01a10d7c-7803-7934-a1d1-a3e43138e938
01a10d7c-7803-7a46-aa46-f905453ac72e
01a10d7c-7803-7b59-9867-d58920482fb7
01a10d7c-7803-7c6b-836b-22481f498a64
01a10d7c-7803-7d7d-b0f0-5f8201b03c6b
01a10d7c-7803-7e90-8fc3-a28e0a795221

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)

1f1c0f0e-1915-6cb8-b6a5-4cf95d479851
1f1c0f0e-1915-6ea2-b6a5-4cf95d479851
1f1c0f0e-1915-6f9c-b6a5-4cf95d479851
1f1c0f0e-1916-606e-b6a5-4cf95d479851
1f1c0f0e-1916-6140-b6a5-4cf95d479851
1f1c0f0e-1916-6212-b6a5-4cf95d479851
1f1c0f0e-1916-62da-b6a5-4cf95d479851
1f1c0f0e-1916-63ac-b6a5-4cf95d479851
1f1c0f0e-1916-647e-b6a5-4cf95d479851
1f1c0f0e-1916-6546-b6a5-4cf95d479851
1f1c0f0e-1916-66b8-b6a5-4cf95d479851
1f1c0f0e-1916-6794-b6a5-4cf95d479851
1f1c0f0e-1916-6866-b6a5-4cf95d479851
1f1c0f0e-1916-692e-b6a5-4cf95d479851
1f1c0f0e-1916-6a00-b6a5-4cf95d479851

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)

e1916adc-c0f0-11f1-b6a5-4cf95d479851
e1916b40-c0f0-11f1-b6a5-4cf95d479851
e1916ba4-c0f0-11f1-b6a5-4cf95d479851
e1916c08-c0f0-11f1-b6a5-4cf95d479851
e1916c6c-c0f0-11f1-b6a5-4cf95d479851
e1916cd0-c0f0-11f1-b6a5-4cf95d479851
e1916d34-c0f0-11f1-b6a5-4cf95d479851
e1916d98-c0f0-11f1-b6a5-4cf95d479851
e1916dfc-c0f0-11f1-b6a5-4cf95d479851
e1916e60-c0f0-11f1-b6a5-4cf95d479851
e1916ec4-c0f0-11f1-b6a5-4cf95d479851
e1916f32-c0f0-11f1-b6a5-4cf95d479851
e1916f96-c0f0-11f1-b6a5-4cf95d479851
e1916ffa-c0f0-11f1-b6a5-4cf95d479851
e191705e-c0f0-11f1-b6a5-4cf95d479851

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)

43d26d2b-8204-8611-87ea-5ce32bd83b97
dfee6e2b-8204-8611-87ea-5ce32bd83b97
f89d6f2b-8204-8611-87ea-5ce32bd83b97
68d5702b-8204-8611-87ea-5ce32bd83b97
651b712b-8204-8611-87ea-5ce32bd83b97
7b7e722b-8204-8611-87ea-5ce32bd83b97
1b58742b-8204-8611-87ea-5ce32bd83b97
16dd752b-8204-8611-87ea-5ce32bd83b97
c29f762b-8204-8611-87ea-5ce32bd83b97
f448772b-8204-8611-87ea-5ce32bd83b97
3720782b-8204-8611-87ea-5ce32bd83b97
b9c2792b-8204-8611-87ea-5ce32bd83b97
be157a2b-8204-8611-87ea-5ce32bd83b97
a5717b2b-8204-8611-87ea-5ce32bd83b97
8bb07c2b-8204-8611-87ea-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)

774d957e-1341-4d7f-95fe-cb2290438cd9
8019175f-aef4-40c1-89a7-1907e57959a5
7a6d3911-5e9a-435f-ae67-022f4b6f54e3
6b044cfc-639a-410e-a174-87a0b7b6bdd1
5fab1046-27db-4956-9866-0466b5cf15c5
6d754217-7df1-4032-9119-3f864711ae06
2143abea-5261-47ea-a3a6-80893b42b81f
394c351e-e16f-4885-8f29-2211843f9788
cde9f20e-45d1-4d56-b74c-e5704d60ab61
d00e7e51-de8d-4476-9713-b024222c9450
58a860fe-5150-4a02-961f-7563b6330e98
cf274fef-04a7-422a-8e97-d053edb8da1c
7ae5d657-4967-41b5-a972-3f5007b0e6d7
076e2b5e-8a08-427d-b830-98b495d2b62c
20d8791d-f27c-4245-881b-cf43b681dfdf

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: