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)

019af243-0814-744e-a5ed-dc3e239eac1c
019af243-0814-75e0-a46c-e635c7ba78fa
019af243-0814-772c-b2dd-86e58c562c22
019af243-0814-784e-b1b6-d34dd9d3b36a
019af243-0814-7971-bbb0-f1c5e9b9c508
019af243-0814-7a90-aa55-a5290b3bbcad
019af243-0814-7baf-af86-1dba4e8ba19b
019af243-0814-7ccd-beba-e8e6d59c58cc
019af243-0814-7dec-aee3-dc6f750cdab0
019af243-0814-7f07-b8a9-3eeef6b5e171
019af243-0815-7025-8cf5-38756d9b1ec3
019af243-0815-7144-9dda-92d5425aa717
019af243-0815-7263-a409-22c63268d82d
019af243-0815-737d-8845-46aa74052ae8
019af243-0815-749c-b6be-e808603327eb

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)

1f0d2696-ded0-6364-93d4-4cf95d479851
1f0d2696-ded0-6544-93d4-4cf95d479851
1f0d2696-ded0-6652-93d4-4cf95d479851
1f0d2696-ded0-6724-93d4-4cf95d479851
1f0d2696-ded0-6814-93d4-4cf95d479851
1f0d2696-ded0-6904-93d4-4cf95d479851
1f0d2696-ded0-69d6-93d4-4cf95d479851
1f0d2696-ded0-6a9e-93d4-4cf95d479851
1f0d2696-ded0-6b66-93d4-4cf95d479851
1f0d2696-ded0-6c2e-93d4-4cf95d479851
1f0d2696-ded0-6d82-93d4-4cf95d479851
1f0d2696-ded0-6e5e-93d4-4cf95d479851
1f0d2696-ded0-6f1c-93d4-4cf95d479851
1f0d2696-ded0-6fe4-93d4-4cf95d479851
1f0d2696-ded1-60ac-93d4-4cf95d479851

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)

fc3d87bd-f439-44d1-8905-782718b85dae
ff80ed4c-2fea-4d58-a07b-1f0e98c39e40
a1ccfb2a-7edc-42fa-b8db-c555a760271a
155c13ab-860a-41c7-b231-c5e42298e092
e6ba9e00-d841-4d8d-a595-b50652583053
eff663b9-4a2b-470f-92d9-79dc37ff073a
f930843f-5efa-4f02-9eee-f44a9cc9fd4a
61cb073d-7716-43bd-9acf-f9e0e8bc3150
09ba14a9-1ed8-4c94-b517-c6690afba26f
0216531e-b644-4dae-b60d-5471cfd371c3
6d15da3c-43a0-4a91-9144-67eda232f2c8
c0e81297-a4b5-4665-8eec-ab3731cfb7f1
fad42b4f-e586-4d77-9834-ef0f745aaa41
414d8ca9-d343-45b1-8590-678636ff9fc4
b1bf0989-741b-4111-868c-c581c7891d7c

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)

6ded15ca-d269-11f0-93d4-4cf95d479851
6ded162e-d269-11f0-93d4-4cf95d479851
6ded1688-d269-11f0-93d4-4cf95d479851
6ded16ec-d269-11f0-93d4-4cf95d479851
6ded1750-d269-11f0-93d4-4cf95d479851
6ded17aa-d269-11f0-93d4-4cf95d479851
6ded180e-d269-11f0-93d4-4cf95d479851
6ded1872-d269-11f0-93d4-4cf95d479851
6ded18cc-d269-11f0-93d4-4cf95d479851
6ded1930-d269-11f0-93d4-4cf95d479851
6ded1994-d269-11f0-93d4-4cf95d479851
6ded19f8-d269-11f0-93d4-4cf95d479851
6ded1a5c-d269-11f0-93d4-4cf95d479851
6ded1ac0-d269-11f0-93d4-4cf95d479851
6ded1b24-d269-11f0-93d4-4cf95d479851

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)

d4ef9d1e-6d01-8415-87e9-5ce32bd83b97
65619e1e-6d01-8415-87e9-5ce32bd83b97
8e569f1e-6d01-8415-87e9-5ce32bd83b97
304da01e-6d01-8415-87e9-5ce32bd83b97
457aa11e-6d01-8415-87e9-5ce32bd83b97
8b0fa21e-6d01-8415-87e9-5ce32bd83b97
9f4ca31e-6d01-8415-87e9-5ce32bd83b97
2a34a41e-6d01-8415-87e9-5ce32bd83b97
c25da51e-6d01-8415-87e9-5ce32bd83b97
6c98a61e-6d01-8415-87e9-5ce32bd83b97
5e2ca71e-6d01-8415-87e9-5ce32bd83b97
11dda81e-6d01-8415-87e9-5ce32bd83b97
1684a91e-6d01-8415-87e9-5ce32bd83b97
ff2aaa1e-6d01-8415-87e9-5ce32bd83b97
e330ab1e-6d01-8415-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: