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)

019acef3-dc88-76d5-9bc8-cdb829629056
019acef3-dc88-78de-b842-fc3bcc248ecb
019acef3-dc88-7a2e-a43b-776092096378
019acef3-dc88-7b50-b3ce-76d2ba34f8db
019acef3-dc88-7c6f-b447-f1ab4082c95f
019acef3-dc88-7d8e-b70c-d483dea31327
019acef3-dc88-7ead-bc06-f11e3e721530
019acef3-dc88-7fcb-84fb-ac2a8d91990a
019acef3-dc89-70e6-b020-962998445160
019acef3-dc89-7205-96f0-feab37bc8e3f
019acef3-dc89-731f-9676-b6244f056b59
019acef3-dc89-743e-97bb-00a8f97ee291
019acef3-dc89-7559-9ab8-eaaa73f9195e
019acef3-dc89-7677-a324-5b46a0fb1b36
019acef3-dc89-7792-8b2f-cde3561c7d78

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)

1f0cd062-9580-600e-8c9d-4cf95d479851
1f0cd062-9580-61da-8c9d-4cf95d479851
1f0cd062-9580-62ca-8c9d-4cf95d479851
1f0cd062-9580-6392-8c9d-4cf95d479851
1f0cd062-9580-6464-8c9d-4cf95d479851
1f0cd062-9580-652c-8c9d-4cf95d479851
1f0cd062-9580-65ea-8c9d-4cf95d479851
1f0cd062-9580-66b2-8c9d-4cf95d479851
1f0cd062-9580-6770-8c9d-4cf95d479851
1f0cd062-9580-6838-8c9d-4cf95d479851
1f0cd062-9580-69aa-8c9d-4cf95d479851
1f0cd062-9580-6a7c-8c9d-4cf95d479851
1f0cd062-9580-6b3a-8c9d-4cf95d479851
1f0cd062-9580-6c0c-8c9d-4cf95d479851
1f0cd062-9580-6cd4-8c9d-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)

22e5ffe2-7428-4256-b25d-cbbf8abfa53a
61a900b5-fed1-454e-bfdf-5b005f6110bd
676d9779-ccf0-437d-af1c-ed9ad8cd5ea9
927a3d17-d124-4c62-8b54-1e64b203641a
5b5abdca-6ed7-4e36-9fe6-fc9f1d060d42
307ab65c-b18e-46ad-bce5-53d9b3090676
c9dfa1ba-715c-4d20-82a3-3999a3d6f73d
a6ea7cd3-1747-4575-9717-29da583eff45
8b3dea6e-9c2e-4bfb-997c-b2e5d09ef9bf
53ea9ec6-5d60-42a4-ba1f-f7b732c081a2
9eb02103-ba8d-485a-8f00-8cec1ec164d7
50911c5e-a9ec-45d1-a308-c8c737edddee
f7b22600-6e37-4858-a8a7-b5698ff5d32e
21599133-e009-4f6c-90e8-16a411bad970
5aecaf22-8760-412b-96ba-eb3781aad657

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)

295811fc-cd06-11f0-8c9d-4cf95d479851
29581260-cd06-11f0-8c9d-4cf95d479851
295812c4-cd06-11f0-8c9d-4cf95d479851
29581332-cd06-11f0-8c9d-4cf95d479851
29581396-cd06-11f0-8c9d-4cf95d479851
295813fa-cd06-11f0-8c9d-4cf95d479851
2958145e-cd06-11f0-8c9d-4cf95d479851
295814c2-cd06-11f0-8c9d-4cf95d479851
29581526-cd06-11f0-8c9d-4cf95d479851
29581580-cd06-11f0-8c9d-4cf95d479851
295815e4-cd06-11f0-8c9d-4cf95d479851
29581648-cd06-11f0-8c9d-4cf95d479851
295816ac-cd06-11f0-8c9d-4cf95d479851
29581710-cd06-11f0-8c9d-4cf95d479851
29581774-cd06-11f0-8c9d-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)

5fcb8f13-3c02-8d14-87e9-5ce32bd83b97
01ca9013-3c02-8d14-87e9-5ce32bd83b97
6dab9113-3c02-8d14-87e9-5ce32bd83b97
833e9313-3c02-8d14-87e9-5ce32bd83b97
2fd79413-3c02-8d14-87e9-5ce32bd83b97
d0f49513-3c02-8d14-87e9-5ce32bd83b97
33339613-3c02-8d14-87e9-5ce32bd83b97
fcc49713-3c02-8d14-87e9-5ce32bd83b97
cbf99813-3c02-8d14-87e9-5ce32bd83b97
0ecf9913-3c02-8d14-87e9-5ce32bd83b97
0f719a13-3c02-8d14-87e9-5ce32bd83b97
2f209b13-3c02-8d14-87e9-5ce32bd83b97
3aa69c13-3c02-8d14-87e9-5ce32bd83b97
03789d13-3c02-8d14-87e9-5ce32bd83b97
c95c9e13-3c02-8d14-87e9-5ce32bd83b97

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: