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)

019bc759-135f-7cea-bf86-f0d5a8752a46
019bc759-135f-7ec9-b6bd-73dfa1315291
019bc759-135f-700d-a1cf-c4da1e000f0d
019bc759-1360-7130-af02-a7ec7a101838
019bc759-1360-724e-a01b-0a022ab1b0d4
019bc759-1360-7369-902a-aa95dcd146b6
019bc759-1360-7484-80eb-93ced87432fe
019bc759-1360-75aa-952f-058ead23cf1c
019bc759-1360-76c5-890b-601f583c7bb7
019bc759-1360-77e0-bc63-2db052861aad
019bc759-1360-78fa-b113-7d9dc8538830
019bc759-1360-7a11-8a63-897468af5247
019bc759-1360-7b2c-bc7b-ddf90b06ab01
019bc759-1360-7c46-a819-b879db304f29
019bc759-1360-7d65-a7ec-b975b3e8e059

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)

1f0f2ed1-b063-6acc-8727-4cf95d479851
1f0f2ed1-b063-6c70-8727-4cf95d479851
1f0f2ed1-b063-6d60-8727-4cf95d479851
1f0f2ed1-b063-6e32-8727-4cf95d479851
1f0f2ed1-b063-6f04-8727-4cf95d479851
1f0f2ed1-b063-6fcc-8727-4cf95d479851
1f0f2ed1-b064-609e-8727-4cf95d479851
1f0f2ed1-b064-6166-8727-4cf95d479851
1f0f2ed1-b064-622e-8727-4cf95d479851
1f0f2ed1-b064-62f6-8727-4cf95d479851
1f0f2ed1-b064-6436-8727-4cf95d479851
1f0f2ed1-b064-6508-8727-4cf95d479851
1f0f2ed1-b064-65c6-8727-4cf95d479851
1f0f2ed1-b064-6684-8727-4cf95d479851
1f0f2ed1-b064-674c-8727-4cf95d479851

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)

488ba79c-0420-47e6-82c5-da41ca70b0df
705d31ef-275b-4940-90c6-1e21704bc63f
69eb7635-b7ce-4cc7-9379-738c6774d9f0
573306c1-8c29-4d8b-b559-349d1e5b1dc7
461e25b8-3442-4ea5-9f8e-97bfe059d3b5
e17d7080-4025-426b-bbc4-e293bc1f3a87
874f6227-4cc2-4396-bfc8-796650050170
665bdbb6-18bc-4032-87f3-ab976578efec
79c65ce9-bb7c-49ab-8209-687f837b9d13
c6f3f4b3-7256-4758-892c-4c5aa71c1d2c
86150192-9eb7-48da-8a85-4027e2368668
d305cbe9-0f80-41fe-863c-8ef11da334ed
c001db31-2b67-4c07-972b-2b0f897d7384
c7c1332c-874b-4c06-a1b5-17ac3aed1961
bb363e96-57a4-4801-9500-0266d741a53a

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)

1b064c7e-f2ed-11f0-8727-4cf95d479851
1b064ce2-f2ed-11f0-8727-4cf95d479851
1b064d46-f2ed-11f0-8727-4cf95d479851
1b064da0-f2ed-11f0-8727-4cf95d479851
1b064dfa-f2ed-11f0-8727-4cf95d479851
1b064e54-f2ed-11f0-8727-4cf95d479851
1b064eb8-f2ed-11f0-8727-4cf95d479851
1b064f1c-f2ed-11f0-8727-4cf95d479851
1b064f76-f2ed-11f0-8727-4cf95d479851
1b064fd0-f2ed-11f0-8727-4cf95d479851
1b065034-f2ed-11f0-8727-4cf95d479851
1b06508e-f2ed-11f0-8727-4cf95d479851
1b0650e8-f2ed-11f0-8727-4cf95d479851
1b06514c-f2ed-11f0-8727-4cf95d479851
1b0651a6-f2ed-11f0-8727-4cf95d479851

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)

5b0e4e2a-8c03-8001-87ea-5ce32bd83b97
b6ee4f2a-8c03-8001-87ea-5ce32bd83b97
1ed1502a-8c03-8001-87ea-5ce32bd83b97
c82a512a-8c03-8001-87ea-5ce32bd83b97
c442522a-8c03-8001-87ea-5ce32bd83b97
21e0532a-8c03-8001-87ea-5ce32bd83b97
2e8e542a-8c03-8001-87ea-5ce32bd83b97
782c552a-8c03-8001-87ea-5ce32bd83b97
81ea562a-8c03-8001-87ea-5ce32bd83b97
369a572a-8c03-8001-87ea-5ce32bd83b97
0ad4582a-8c03-8001-87ea-5ce32bd83b97
1471592a-8c03-8001-87ea-5ce32bd83b97
dc2e5a2a-8c03-8001-87ea-5ce32bd83b97
f40b5b2a-8c03-8001-87ea-5ce32bd83b97
5f1b5c2a-8c03-8001-87ea-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: