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)

019bf999-9fea-7b3c-87a6-48db2b97da01
019bf999-9fea-7cc9-827c-73b1920992af
019bf999-9fea-7e42-b9ef-ba21d0155b60
019bf999-9fea-7f92-9cac-2bcbca7f7124
019bf999-9feb-70b5-8543-2bb1ec7b1657
019bf999-9feb-71cf-a2c0-3813b82b5f69
019bf999-9feb-72ea-a11a-0eca27ae71d0
019bf999-9feb-7400-be51-4f363bb2fd72
019bf999-9feb-751b-8cd0-21c757e0fd55
019bf999-9feb-7636-a4c7-754991ed73c7
019bf999-9feb-7750-b7d7-90fe5eb11f9b
019bf999-9feb-786f-89c6-b8ba49bc0c28
019bf999-9feb-798a-bc10-50d968c534b9
019bf999-9feb-7aa0-95d6-51410920a43f
019bf999-9feb-7b1f-b47c-eaed9392d75a

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)

1f0fa981-4782-6aa0-8e73-4cf95d479851
1f0fa981-4782-6c30-8e73-4cf95d479851
1f0fa981-4782-6d16-8e73-4cf95d479851
1f0fa981-4782-6e88-8e73-4cf95d479851
1f0fa981-4783-600e-8e73-4cf95d479851
1f0fa981-4783-619e-8e73-4cf95d479851
1f0fa981-4783-631a-8e73-4cf95d479851
1f0fa981-4783-640a-8e73-4cf95d479851
1f0fa981-4783-64d2-8e73-4cf95d479851
1f0fa981-4783-659a-8e73-4cf95d479851
1f0fa981-4783-66e4-8e73-4cf95d479851
1f0fa981-4783-67b6-8e73-4cf95d479851
1f0fa981-4783-6874-8e73-4cf95d479851
1f0fa981-4783-693c-8e73-4cf95d479851
1f0fa981-4783-6a04-8e73-4cf95d479851

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)

aef02582-9049-4d97-bee4-cf905f8e7d9e
14093e7d-1643-4ad2-89ef-40d25ac992b3
b982598c-f7ca-4bd5-9637-a61ff281231e
ee36ef06-4424-4cc0-89c0-d49586bc2a61
486e201d-db80-4e77-99d0-73b9bc523130
3a2b2e37-5148-463e-a5de-e06bd7703237
a94161b6-2f81-4c21-927b-efcbe253f825
4c05bbe0-f718-407c-b359-11a843734817
9414ecb9-96f6-46ca-a1df-8c482a7cd5bd
d48a7ead-a1aa-4123-9428-303003bef3eb
510eae13-65d2-4c5a-beda-9c1a2d0b7f98
b7114fd7-08ea-4c29-9552-0e5b9599bd72
45f87865-3618-4a15-a695-6b74da9abfdc
21afc9aa-5f34-4dd1-a812-130bb54ac346
84815e9f-e489-4fd3-9c03-7ec328fccfc1

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)

14783f36-fa98-11f0-8e73-4cf95d479851
14783fae-fa98-11f0-8e73-4cf95d479851
14784012-fa98-11f0-8e73-4cf95d479851
1478406c-fa98-11f0-8e73-4cf95d479851
147840d0-fa98-11f0-8e73-4cf95d479851
14784134-fa98-11f0-8e73-4cf95d479851
14784198-fa98-11f0-8e73-4cf95d479851
147841f2-fa98-11f0-8e73-4cf95d479851
14784256-fa98-11f0-8e73-4cf95d479851
147842b0-fa98-11f0-8e73-4cf95d479851
14784314-fa98-11f0-8e73-4cf95d479851
14784378-fa98-11f0-8e73-4cf95d479851
147843d2-fa98-11f0-8e73-4cf95d479851
14784436-fa98-11f0-8e73-4cf95d479851
1478449a-fa98-11f0-8e73-4cf95d479851

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)

b4a1630d-3002-8a01-87ea-5ce32bd83b97
c7aa640d-3002-8a01-87ea-5ce32bd83b97
9a0a650d-3002-8a01-87ea-5ce32bd83b97
1066660d-3002-8a01-87ea-5ce32bd83b97
d429670d-3002-8a01-87ea-5ce32bd83b97
9497680d-3002-8a01-87ea-5ce32bd83b97
b0d4690d-3002-8a01-87ea-5ce32bd83b97
dd576a0d-3002-8a01-87ea-5ce32bd83b97
d73d6b0d-3002-8a01-87ea-5ce32bd83b97
eafb6c0d-3002-8a01-87ea-5ce32bd83b97
1c8c6e0d-3002-8a01-87ea-5ce32bd83b97
5d3b6f0d-3002-8a01-87ea-5ce32bd83b97
a41d700d-3002-8a01-87ea-5ce32bd83b97
62d0710d-3002-8a01-87ea-5ce32bd83b97
4323720d-3002-8a01-87ea-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: