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)

019b5456-35e1-7d69-83e1-3f87d8e18894
019b5456-35e1-7f30-80f6-5a38fbac3cb5
019b5456-35e2-70cd-a291-ee8f432e8b10
019b5456-35e2-722e-acc0-3ecb8a6cc737
019b5456-35e2-7375-88d9-6f4fe54fc718
019b5456-35e2-74da-9a0b-44bfcbcc55aa
019b5456-35e2-763e-8017-51f374d702ab
019b5456-35e2-7786-9295-b24a819d81d8
019b5456-35e2-78e6-a89b-d63539e8161b
019b5456-35e2-7a4e-886e-3e14485df806
019b5456-35e2-7b92-96fa-f021a5900e94
019b5456-35e2-7ce6-a15e-db0d67909f99
019b5456-35e2-7e52-ab4b-186a3769a26c
019b5456-35e2-7fa6-8ed4-5c2aa4843950
019b5456-35e3-70e6-a977-bc40914116bf

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)

1f0e1607-b1a3-6a06-a451-4cf95d479851
1f0e1607-b1a3-6c86-a451-4cf95d479851
1f0e1607-b1a3-6dc6-a451-4cf95d479851
1f0e1607-b1a3-6e98-a451-4cf95d479851
1f0e1607-b1a3-6f88-a451-4cf95d479851
1f0e1607-b1a4-60fa-a451-4cf95d479851
1f0e1607-b1a4-628a-a451-4cf95d479851
1f0e1607-b1a4-63f2-a451-4cf95d479851
1f0e1607-b1a4-6564-a451-4cf95d479851
1f0e1607-b1a4-66d6-a451-4cf95d479851
1f0e1607-b1a4-68de-a451-4cf95d479851
1f0e1607-b1a4-6a28-a451-4cf95d479851
1f0e1607-b1a4-6afa-a451-4cf95d479851
1f0e1607-b1a4-6bb8-a451-4cf95d479851
1f0e1607-b1a4-6cc6-a451-4cf95d479851

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)

26cc091c-66cf-4a9d-8531-18a4a9af867b
959c3e51-8a81-4758-92dd-c34dd1f643de
ac8c20d4-a38f-43bd-abf9-2fecadd2df0a
a17b94b6-de38-4a8f-b6b6-e03e669875a3
9e0bd9fd-dc74-4dd6-a434-e427284a513b
8fef931d-668c-4f51-a86a-3353a32d7c72
ae222057-b633-408b-a769-74fe6dc2908f
f2839801-3fe8-4419-a7c6-de972e2ecce0
117daee7-8061-461b-bb55-1dc5d84cfb46
8f94f272-f4a6-42dd-8c8c-d14e9abddbe4
22e48d35-2d32-49e7-a5e8-a65ddeacb02e
5db01da9-f1ae-498e-859d-e77010ab522b
11a2e67e-a50b-4d66-a7de-cb4b4e7f22cf
d5106de6-bdf6-4615-b0d5-1b68eed13bfb
b6cbb959-b505-4c85-acab-a843bcee72c6

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)

7b1a5414-e160-11f0-a451-4cf95d479851
7b1a54c8-e160-11f0-a451-4cf95d479851
7b1a555e-e160-11f0-a451-4cf95d479851
7b1a55f4-e160-11f0-a451-4cf95d479851
7b1a568a-e160-11f0-a451-4cf95d479851
7b1a5720-e160-11f0-a451-4cf95d479851
7b1a57ac-e160-11f0-a451-4cf95d479851
7b1a5810-e160-11f0-a451-4cf95d479851
7b1a5874-e160-11f0-a451-4cf95d479851
7b1a58e2-e160-11f0-a451-4cf95d479851
7b1a593c-e160-11f0-a451-4cf95d479851
7b1a59c8-e160-11f0-a451-4cf95d479851
7b1a5a5e-e160-11f0-a451-4cf95d479851
7b1a5af4-e160-11f0-a451-4cf95d479851
7b1a5b8a-e160-11f0-a451-4cf95d479851

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)

efdfb10e-ad01-8716-87e9-5ce32bd83b97
9ee2b20e-ad01-8716-87e9-5ce32bd83b97
a3f9b30e-ad01-8716-87e9-5ce32bd83b97
e1b9b40e-ad01-8716-87e9-5ce32bd83b97
adc3b50e-ad01-8716-87e9-5ce32bd83b97
fcf1b60e-ad01-8716-87e9-5ce32bd83b97
9d95b70e-ad01-8716-87e9-5ce32bd83b97
d3ecb80e-ad01-8716-87e9-5ce32bd83b97
5151b90e-ad01-8716-87e9-5ce32bd83b97
acb2ba0e-ad01-8716-87e9-5ce32bd83b97
5b58bb0e-ad01-8716-87e9-5ce32bd83b97
b2bdbc0e-ad01-8716-87e9-5ce32bd83b97
9c54bd0e-ad01-8716-87e9-5ce32bd83b97
4912be0e-ad01-8716-87e9-5ce32bd83b97
6c15bf0e-ad01-8716-87e9-5ce32bd83b97

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

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: