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)

019cf791-3d7d-7b96-9c5c-7fa801f7d87a
019cf791-3d7d-7d8e-9884-43586a67ee5f
019cf791-3d7d-7f1b-a4e2-9a4d523dfea0
019cf791-3d7e-707b-88f0-269a7bad5814
019cf791-3d7e-71d8-8b2f-e00820cda959
019cf791-3d7e-7348-a1bf-609680134c32
019cf791-3d7e-74ad-b84f-ca41f4058793
019cf791-3d7e-7600-9f8b-664338f8787d
019cf791-3d7e-775d-bd36-73b2c3c365b4
019cf791-3d7e-78bd-bad4-5a7b95f27de6
019cf791-3d7e-7a21-8cb4-e2e1696f83ac
019cf791-3d7e-7b71-a6a1-ebf048229b2a
019cf791-3d7e-7cc9-9a34-19124f582dc5
019cf791-3d7e-7ed1-902f-f07c8ad4087b
019cf791-3d7f-7036-9be8-765efebffcb1

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)

1f12158a-cf37-660e-8378-4cf95d479851
1f12158a-cf37-68b6-8378-4cf95d479851
1f12158a-cf37-6a6e-8378-4cf95d479851
1f12158a-cf37-6bf4-8378-4cf95d479851
1f12158a-cf37-6d7a-8378-4cf95d479851
1f12158a-cf37-6ef6-8378-4cf95d479851
1f12158a-cf38-607c-8378-4cf95d479851
1f12158a-cf38-61f8-8378-4cf95d479851
1f12158a-cf38-6360-8378-4cf95d479851
1f12158a-cf38-64c8-8378-4cf95d479851
1f12158a-cf38-66c6-8378-4cf95d479851
1f12158a-cf38-6842-8378-4cf95d479851
1f12158a-cf38-69aa-8378-4cf95d479851
1f12158a-cf38-6b08-8378-4cf95d479851
1f12158a-cf38-6c70-8378-4cf95d479851

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)

47b0f7ca-856c-4fc2-aded-e8eb7ccf0e91
ea78e927-220b-4256-8998-b6b31b768b31
98f19168-3ec6-460a-b44e-9852364fc92e
414ffed3-7941-4708-bfab-e1abdd4ee43b
d1956d6c-69dc-44b2-aede-ce30f5923794
52bebbe4-c927-4687-b58b-ae027d0f86f4
3ec6f357-e61d-49ce-8b99-21ba38eaa009
8881f310-aa85-4709-88ca-adb65d8c8875
4499f7fe-6bb0-4e93-ba73-e1a34e3231cb
8b17f2e4-caf4-48ba-a476-f31c872a63c0
13b911a3-ef92-43bc-beb7-7affd866772b
3ed86264-f37f-4b32-99f6-079d1620aceb
17a02ba7-c73b-46ac-8bab-55c633f6e939
6f2601b1-7f84-4430-8672-5ebbe44ed2b1
b60bd815-d649-467e-85be-091ccb8a3c6a

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)

acf393e6-2158-11f1-8378-4cf95d479851
acf3947c-2158-11f1-8378-4cf95d479851
acf39512-2158-11f1-8378-4cf95d479851
acf395a8-2158-11f1-8378-4cf95d479851
acf3963e-2158-11f1-8378-4cf95d479851
acf396d4-2158-11f1-8378-4cf95d479851
acf39760-2158-11f1-8378-4cf95d479851
acf397ec-2158-11f1-8378-4cf95d479851
acf39878-2158-11f1-8378-4cf95d479851
acf39918-2158-11f1-8378-4cf95d479851
acf399c2-2158-11f1-8378-4cf95d479851
acf39a6c-2158-11f1-8378-4cf95d479851
acf39af8-2158-11f1-8378-4cf95d479851
acf39b8e-2158-11f1-8378-4cf95d479851
acf39c24-2158-11f1-8378-4cf95d479851

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)

e437c424-f603-8b04-87ea-5ce32bd83b97
1e88c524-f603-8b04-87ea-5ce32bd83b97
7abfc624-f603-8b04-87ea-5ce32bd83b97
d765c724-f603-8b04-87ea-5ce32bd83b97
c8d0c824-f603-8b04-87ea-5ce32bd83b97
4d73c924-f603-8b04-87ea-5ce32bd83b97
82fdca24-f603-8b04-87ea-5ce32bd83b97
d254cb24-f603-8b04-87ea-5ce32bd83b97
c54dcc24-f603-8b04-87ea-5ce32bd83b97
5407cd24-f603-8b04-87ea-5ce32bd83b97
b525cf24-f603-8b04-87ea-5ce32bd83b97
e4afd024-f603-8b04-87ea-5ce32bd83b97
31fbd124-f603-8b04-87ea-5ce32bd83b97
3825d224-f603-8b04-87ea-5ce32bd83b97
e9e3d324-f603-8b04-87ea-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: