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)

019abc59-3a21-7196-a270-dc14277e03c9
019abc59-3a21-7344-af5b-f10b691242a0
019abc59-3a21-7490-af31-9bdfbfb1f648
019abc59-3a21-75b3-821a-4b5a8da58e62
019abc59-3a21-76cd-a3b8-64606a917c0a
019abc59-3a21-77e8-b6a3-775e30eb935b
019abc59-3a21-7903-b9cc-973a2e070ed6
019abc59-3a21-7a05-af95-d80b5e45fade
019abc59-3a21-7b1f-8775-8dedbce56a86
019abc59-3a21-7c3a-aae9-85b95efd3956
019abc59-3a21-7d50-91f2-5fb67d20832e
019abc59-3a21-7e67-b2c0-0223b7310f58
019abc59-3a21-7f82-b430-38109d6a7910
019abc59-3a22-709c-a050-2e55c72ed97a
019abc59-3a22-71b7-a052-16087b816aa5

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)

1f0ca2f7-0f01-69c6-a038-4cf95d479851
1f0ca2f7-0f01-6b56-a038-4cf95d479851
1f0ca2f7-0f01-6c3c-a038-4cf95d479851
1f0ca2f7-0f01-6d0e-a038-4cf95d479851
1f0ca2f7-0f01-6dd6-a038-4cf95d479851
1f0ca2f7-0f01-6e94-a038-4cf95d479851
1f0ca2f7-0f01-6f52-a038-4cf95d479851
1f0ca2f7-0f02-6010-a038-4cf95d479851
1f0ca2f7-0f02-60ce-a038-4cf95d479851
1f0ca2f7-0f02-618c-a038-4cf95d479851
1f0ca2f7-0f02-62cc-a038-4cf95d479851
1f0ca2f7-0f02-638a-a038-4cf95d479851
1f0ca2f7-0f02-6448-a038-4cf95d479851
1f0ca2f7-0f02-6510-a038-4cf95d479851
1f0ca2f7-0f02-65c4-a038-4cf95d479851

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)

b2f338ee-98aa-41a3-ac59-8bb4b86b53e5
1a47b58d-e54c-4901-b50d-71df20dbe74d
10d55bce-6398-48cd-afcc-a87aa5da1abb
ecdad559-8dac-40a5-a88f-ce5065858135
8e2badee-01bf-49ee-a9ac-b241dcf92071
e9917bba-59f5-439b-9f1f-449eaafbdcdf
33b89346-fc1d-4e7f-8749-60320418c9f3
7ca8e8d6-c81a-4bd1-897d-41ca09f6e07a
a9e0fc10-0931-4d68-ac8b-4461b81e7ce5
2f70e091-acc5-4c5a-9bcb-a2daffafa865
3614a9d9-27d0-4676-84fb-de460b471025
8355d128-5c9f-43e0-a1c7-fc6bb3a84b8c
b2e5e8a6-4da7-416f-90b0-f00728c39e1e
13862a3e-7d06-4774-ace1-1246066170eb
af92b7e2-ecd9-4ba3-a43a-c7731ae9dd29

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)

70f02ace-ca2f-11f0-a038-4cf95d479851
70f02b32-ca2f-11f0-a038-4cf95d479851
70f02b8c-ca2f-11f0-a038-4cf95d479851
70f02be6-ca2f-11f0-a038-4cf95d479851
70f02c4a-ca2f-11f0-a038-4cf95d479851
70f02ca4-ca2f-11f0-a038-4cf95d479851
70f02d08-ca2f-11f0-a038-4cf95d479851
70f02d6c-ca2f-11f0-a038-4cf95d479851
70f02dc6-ca2f-11f0-a038-4cf95d479851
70f02e20-ca2f-11f0-a038-4cf95d479851
70f02e84-ca2f-11f0-a038-4cf95d479851
70f02ef2-ca2f-11f0-a038-4cf95d479851
70f02f56-ca2f-11f0-a038-4cf95d479851
70f02fc4-ca2f-11f0-a038-4cf95d479851
70f03028-ca2f-11f0-a038-4cf95d479851

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)

871e8d0f-6a04-8914-87e9-5ce32bd83b97
58268e0f-6a04-8914-87e9-5ce32bd83b97
9deb900f-6a04-8914-87e9-5ce32bd83b97
90e9910f-6a04-8914-87e9-5ce32bd83b97
4560920f-6a04-8914-87e9-5ce32bd83b97
b8a7930f-6a04-8914-87e9-5ce32bd83b97
dc53940f-6a04-8914-87e9-5ce32bd83b97
1e7f950f-6a04-8914-87e9-5ce32bd83b97
4b3c960f-6a04-8914-87e9-5ce32bd83b97
f349970f-6a04-8914-87e9-5ce32bd83b97
2444980f-6a04-8914-87e9-5ce32bd83b97
e866990f-6a04-8914-87e9-5ce32bd83b97
f7b29a0f-6a04-8914-87e9-5ce32bd83b97
89059b0f-6a04-8914-87e9-5ce32bd83b97
c6049c0f-6a04-8914-87e9-5ce32bd83b97

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: