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)

019c793e-70e4-76ee-9b98-a2a9e5550fce
019c793e-70e4-78bd-b318-99797e23b4d5
019c793e-70e4-7a05-afb6-abc6f0a551dd
019c793e-70e4-7b27-98ad-33c9767ada4e
019c793e-70e4-7c4e-b211-8a4b8377a15f
019c793e-70e4-7d69-a63c-5f36841bc5ff
019c793e-70e4-7e84-afbe-07c73070345f
019c793e-70e4-7fa2-9b11-c20e471b209c
019c793e-70e5-70b9-8afb-bfeae723396c
019c793e-70e5-71d8-8d80-44c6b85ed695
019c793e-70e5-72f2-89df-e2e6a04d1e8d
019c793e-70e5-740d-9c6b-e73932fe1648
019c793e-70e5-7527-8fd4-3d85177e0b4a
019c793e-70e5-7642-9d85-46df23578a21
019c793e-70e5-775d-9d3c-8fb2f766222c

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)

1f10e122-a9b4-68de-a500-4cf95d479851
1f10e122-a9b4-6a8c-a500-4cf95d479851
1f10e122-a9b4-6b72-a500-4cf95d479851
1f10e122-a9b4-6c3a-a500-4cf95d479851
1f10e122-a9b4-6d02-a500-4cf95d479851
1f10e122-a9b4-6dc0-a500-4cf95d479851
1f10e122-a9b4-6e7e-a500-4cf95d479851
1f10e122-a9b4-6f3c-a500-4cf95d479851
1f10e122-a9b4-6ffa-a500-4cf95d479851
1f10e122-a9b5-60b8-a500-4cf95d479851
1f10e122-a9b5-625c-a500-4cf95d479851
1f10e122-a9b5-63a6-a500-4cf95d479851
1f10e122-a9b5-648c-a500-4cf95d479851
1f10e122-a9b5-654a-a500-4cf95d479851
1f10e122-a9b5-6608-a500-4cf95d479851

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)

4b2e5012-0b67-42b4-85ca-870353db6711
6c2bc1f1-3e0c-4095-9bdf-753e909bbe10
da710c45-adf7-41ee-9c73-0f2d93a12e42
123a0236-6e2d-475a-a346-2816051f41e9
81243210-5604-4031-80c3-ec2bd0801d55
26ab9f3b-9ac3-475d-aaa7-a5ac5e7aa5c4
3060d9a8-61f3-4668-916b-3efa581712f7
086684fa-8fcc-4cb9-bf8d-497ee8c264e6
97213157-b3d2-40af-88ea-3926fcb1287a
186b0e7f-8fa4-4db0-887f-3dad27283758
3771df50-df3b-41ef-ae3f-266a2d3c1bdd
fdd4f8be-da42-46a5-931c-2f6605144e70
78166c95-8725-4bbe-8635-b5f4ad537353
53148898-f311-4a1c-a3f4-2fd77547b68b
e8021b3a-b1e2-4e79-84aa-86a2164625f5

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)

2a9b5b30-0e12-11f1-a500-4cf95d479851
2a9b5b8a-0e12-11f1-a500-4cf95d479851
2a9b5bee-0e12-11f1-a500-4cf95d479851
2a9b5c52-0e12-11f1-a500-4cf95d479851
2a9b5cac-0e12-11f1-a500-4cf95d479851
2a9b5d10-0e12-11f1-a500-4cf95d479851
2a9b5d6a-0e12-11f1-a500-4cf95d479851
2a9b5dd8-0e12-11f1-a500-4cf95d479851
2a9b5e3c-0e12-11f1-a500-4cf95d479851
2a9b5e96-0e12-11f1-a500-4cf95d479851
2a9b5f04-0e12-11f1-a500-4cf95d479851
2a9b5f72-0e12-11f1-a500-4cf95d479851
2a9b5fcc-0e12-11f1-a500-4cf95d479851
2a9b6030-0e12-11f1-a500-4cf95d479851
2a9b6094-0e12-11f1-a500-4cf95d479851

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)

ee7f3901-fc00-8303-87ea-5ce32bd83b97
05873a01-fc00-8303-87ea-5ce32bd83b97
3cc53b01-fc00-8303-87ea-5ce32bd83b97
1c563c01-fc00-8303-87ea-5ce32bd83b97
886c3d01-fc00-8303-87ea-5ce32bd83b97
62c03e01-fc00-8303-87ea-5ce32bd83b97
d32f3f01-fc00-8303-87ea-5ce32bd83b97
b3604001-fc00-8303-87ea-5ce32bd83b97
4e644101-fc00-8303-87ea-5ce32bd83b97
d9044201-fc00-8303-87ea-5ce32bd83b97
922f4301-fc00-8303-87ea-5ce32bd83b97
8d9d4401-fc00-8303-87ea-5ce32bd83b97
a6474501-fc00-8303-87ea-5ce32bd83b97
100d4601-fc00-8303-87ea-5ce32bd83b97
cfe04701-fc00-8303-87ea-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: