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)

019d2c4e-6d60-7605-8dff-a205dabb8170
019d2c4e-6d60-77af-9110-60c16e72b270
019d2c4e-6d60-7913-b470-a2cc9b06c77c
019d2c4e-6d60-7a36-8f20-21fb052fb2ea
019d2c4e-6d60-7ade-89eb-b48f42f161a4
019d2c4e-6d60-7c15-a542-7718078c82ee
019d2c4e-6d60-7d34-b70b-0a5d224fd943
019d2c4e-6d60-7e52-a7c1-b1e6c23b1b85
019d2c4e-6d60-7f6d-851d-b099964210d7
019d2c4e-6d61-708c-b85a-45005854e360
019d2c4e-6d61-71a6-8d2c-9a1c6abe0e4f
019d2c4e-6d61-72c1-b25c-870298a3ef2b
019d2c4e-6d61-73e0-a3a5-5db8122324ef
019d2c4e-6d61-750f-987e-bfabd831ec83
019d2c4e-6d61-762e-bc6f-3cd211072c6b

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)

1f12964c-b11f-6084-aa46-4cf95d479851
1f12964c-b11f-6232-aa46-4cf95d479851
1f12964c-b11f-6318-aa46-4cf95d479851
1f12964c-b11f-63ea-aa46-4cf95d479851
1f12964c-b11f-64a8-aa46-4cf95d479851
1f12964c-b11f-6570-aa46-4cf95d479851
1f12964c-b11f-662e-aa46-4cf95d479851
1f12964c-b11f-66f6-aa46-4cf95d479851
1f12964c-b11f-67b4-aa46-4cf95d479851
1f12964c-b11f-687c-aa46-4cf95d479851
1f12964c-b11f-69bc-aa46-4cf95d479851
1f12964c-b11f-6a8e-aa46-4cf95d479851
1f12964c-b11f-6b4c-aa46-4cf95d479851
1f12964c-b11f-6c14-aa46-4cf95d479851
1f12964c-b11f-6cd2-aa46-4cf95d479851

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)

f638117c-3f89-4ac8-9b36-bd2e899ab90b
42fb01a2-1f9a-4c9c-b0f8-c195d7f975ed
3aaa3f95-08f3-4d60-9272-d2f5ca8d0f97
7588b7c7-ee52-4867-875f-db8acf45a628
1cc49b26-6242-4244-b3a8-7e414cd312e7
e3618eb0-40f7-46df-b95d-dbfcf37eee28
01d9e5c4-6966-4f9a-930f-30b35d069406
67a95610-ee1d-4532-826c-98fb1385504d
88d5caf4-32f6-4645-86ed-f5225eb7ef47
0c5c7b52-8fdd-4047-b990-b6bdc2d7a093
74d90caa-4bf1-4e71-bcd5-be87751e62d9
8cda74b6-0372-4ff2-94e9-5f0c447b77e6
0a045f90-99f5-458d-a656-9cc88c399805
80d3e8b7-7e51-43a8-86eb-4075ee8f0729
bcedecab-bbc9-49a7-8011-c8ea05f35286

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)

cb1201fa-2964-11f1-aa46-4cf95d479851
cb12025e-2964-11f1-aa46-4cf95d479851
cb1202b8-2964-11f1-aa46-4cf95d479851
cb12031c-2964-11f1-aa46-4cf95d479851
cb120380-2964-11f1-aa46-4cf95d479851
cb1203e4-2964-11f1-aa46-4cf95d479851
cb12043e-2964-11f1-aa46-4cf95d479851
cb1204a2-2964-11f1-aa46-4cf95d479851
cb120510-2964-11f1-aa46-4cf95d479851
cb120574-2964-11f1-aa46-4cf95d479851
cb1205e2-2964-11f1-aa46-4cf95d479851
cb12063c-2964-11f1-aa46-4cf95d479851
cb1206a0-2964-11f1-aa46-4cf95d479851
cb120704-2964-11f1-aa46-4cf95d479851
cb120768-2964-11f1-aa46-4cf95d479851

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)

9cdd8f1e-5105-8505-87ea-5ce32bd83b97
f2a4901e-5105-8505-87ea-5ce32bd83b97
4070911e-5105-8505-87ea-5ce32bd83b97
d588931e-5105-8505-87ea-5ce32bd83b97
52e9941e-5105-8505-87ea-5ce32bd83b97
e539951e-5105-8505-87ea-5ce32bd83b97
af89961e-5105-8505-87ea-5ce32bd83b97
a6a2971e-5105-8505-87ea-5ce32bd83b97
b490981e-5105-8505-87ea-5ce32bd83b97
4adb991e-5105-8505-87ea-5ce32bd83b97
7d909a1e-5105-8505-87ea-5ce32bd83b97
3cc69b1e-5105-8505-87ea-5ce32bd83b97
6ebe9c1e-5105-8505-87ea-5ce32bd83b97
597e9d1e-5105-8505-87ea-5ce32bd83b97
e3d09e1e-5105-8505-87ea-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: