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)

019a0019-8d5a-7c00-a9b8-c85583c90690
019a0019-8d5a-7d96-b0e2-c84c4476599f
019a0019-8d5a-7eee-807d-56b899223150
019a0019-8d5b-7090-ba94-011d78e92d6b
019a0019-8d5b-7211-b708-989937a08b28
019a0019-8d5b-7365-bef9-50e779ee6447
019a0019-8d5b-74ad-808d-0bfff5f09667
019a0019-8d5b-75f4-a7d4-0deeed1007fe
019a0019-8d5b-7734-9b00-b1f2faeb9b14
019a0019-8d5b-7877-9899-9b4c9ff8c4b2
019a0019-8d5b-79bb-944b-10078333e102
019a0019-8d5b-7b03-9349-e1f20a26efd8
019a0019-8d5b-7c42-80d9-05c807fe00cb
019a0019-8d5b-7d8a-b0e1-9ba5a661965a
019a0019-8d5b-7ecd-b01e-1f595358d15d

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)

1f0ad75f-9a31-6bb4-946e-4cf95d479851
1f0ad75f-9a31-6e3e-946e-4cf95d479851
1f0ad75f-9a31-6fe2-946e-4cf95d479851
1f0ad75f-9a32-6154-946e-4cf95d479851
1f0ad75f-9a32-62c6-946e-4cf95d479851
1f0ad75f-9a32-642e-946e-4cf95d479851
1f0ad75f-9a32-6596-946e-4cf95d479851
1f0ad75f-9a32-6708-946e-4cf95d479851
1f0ad75f-9a32-6870-946e-4cf95d479851
1f0ad75f-9a32-69d8-946e-4cf95d479851
1f0ad75f-9a32-6bf4-946e-4cf95d479851
1f0ad75f-9a32-6d70-946e-4cf95d479851
1f0ad75f-9a32-6ed8-946e-4cf95d479851
1f0ad75f-9a33-6040-946e-4cf95d479851
1f0ad75f-9a33-619e-946e-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)

62203722-9156-4951-b290-ad9d53d98df5
60b85103-4e4a-42ce-8f56-8615813d3c18
3b69001c-aba3-4ae1-b9dc-b66d7d5b2a79
7d4460e3-2749-4d00-8cee-1ae98384b2aa
887ac117-6e43-4822-904a-ffd41f25af3d
b563ac2d-ef75-46bf-9af6-b92db5b12585
109b740a-966a-448c-86b6-353f8fe8ba25
0b8c6155-33a7-46a4-99a2-b92a281167ac
ab0d08ab-92b9-437f-a605-b37d3b1a4430
9ff560c7-81f9-4621-8d72-df5c61e48b30
06a8552e-ed5e-426d-828b-af0166a82bc6
9499dacd-0391-4799-8476-f556112a0b4e
9b07200b-e82b-450a-8ea2-fcd68977056f
f54e2526-b506-4ea7-9aff-26a5e6713f6c
9f0fa65f-f143-42f8-939b-b44b818bf74d

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)

f9a3398c-ad75-11f0-946e-4cf95d479851
f9a33a36-ad75-11f0-946e-4cf95d479851
f9a33ad6-ad75-11f0-946e-4cf95d479851
f9a33b6c-ad75-11f0-946e-4cf95d479851
f9a33c02-ad75-11f0-946e-4cf95d479851
f9a33ca2-ad75-11f0-946e-4cf95d479851
f9a33d38-ad75-11f0-946e-4cf95d479851
f9a33dce-ad75-11f0-946e-4cf95d479851
f9a33e6e-ad75-11f0-946e-4cf95d479851
f9a33f04-ad75-11f0-946e-4cf95d479851
f9a33fa4-ad75-11f0-946e-4cf95d479851
f9a3403a-ad75-11f0-946e-4cf95d479851
f9a340d0-ad75-11f0-946e-4cf95d479851
f9a34166-ad75-11f0-946e-4cf95d479851
f9a34210-ad75-11f0-946e-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)

69c4f205-4c01-8512-87e9-5ce32bd83b97
de62f305-4c01-8512-87e9-5ce32bd83b97
97e3f405-4c01-8512-87e9-5ce32bd83b97
4107f505-4c01-8512-87e9-5ce32bd83b97
c0b2f605-4c01-8512-87e9-5ce32bd83b97
ab1df705-4c01-8512-87e9-5ce32bd83b97
ef90f805-4c01-8512-87e9-5ce32bd83b97
d99df905-4c01-8512-87e9-5ce32bd83b97
ce69fb05-4c01-8512-87e9-5ce32bd83b97
1c21fc05-4c01-8512-87e9-5ce32bd83b97
3762fd05-4c01-8512-87e9-5ce32bd83b97
78e6fe05-4c01-8512-87e9-5ce32bd83b97
7606ff05-4c01-8512-87e9-5ce32bd83b97
24d80106-4c01-8512-87e9-5ce32bd83b97
26950206-4c01-8512-87e9-5ce32bd83b97

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: