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)

019ae185-3835-7e25-8e8d-958a9d67e850
019ae185-3835-7fdc-9034-512c2075aed5
019ae185-3836-711f-b65d-7a4c480721c5
019ae185-3836-7246-8f2d-c84071b5a8fc
019ae185-3836-7361-a1db-5be844d12760
019ae185-3836-747f-b3fe-9013f728edf0
019ae185-3836-759a-9434-98985d019c8c
019ae185-3836-76b9-85ca-f921bf0be29a
019ae185-3836-77d3-9256-2322f71642e7
019ae185-3836-78ee-b19f-3f0c36e9b65f
019ae185-3836-7a09-a9d9-f88907c28afb
019ae185-3836-7b27-8df4-b35cdedb1805
019ae185-3836-7c46-9af3-f7db3c136651
019ae185-3836-7d61-bcf0-66c50e1cb043
019ae185-3836-7e7b-a800-cbd77fc8e304

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)

1f0cfdb7-7652-660a-b910-4cf95d479851
1f0cfdb7-7652-67ae-b910-4cf95d479851
1f0cfdb7-7652-689e-b910-4cf95d479851
1f0cfdb7-7652-6970-b910-4cf95d479851
1f0cfdb7-7652-6a38-b910-4cf95d479851
1f0cfdb7-7652-6b00-b910-4cf95d479851
1f0cfdb7-7652-6bc8-b910-4cf95d479851
1f0cfdb7-7652-6c90-b910-4cf95d479851
1f0cfdb7-7652-6d4e-b910-4cf95d479851
1f0cfdb7-7652-6e16-b910-4cf95d479851
1f0cfdb7-7652-6f60-b910-4cf95d479851
1f0cfdb7-7653-603c-b910-4cf95d479851
1f0cfdb7-7653-60fa-b910-4cf95d479851
1f0cfdb7-7653-61c2-b910-4cf95d479851
1f0cfdb7-7653-6280-b910-4cf95d479851

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)

fc0a7516-2e80-4424-9b5f-b40b9cbd8f23
8491216a-6628-44e5-bc02-f2443facfcaf
2bc1141a-1080-4a5a-a8f4-b755676fc148
cb918430-2a06-4e0e-8496-69caf8f978ec
0648136c-444b-4e54-bc4d-50dad059ead1
67944648-9819-4354-8abb-2e20d4f61231
513792d8-c8f6-4246-b1e6-c3ad156c53d5
0dbd33d5-3083-4405-94dc-cc94509c1fde
29530b17-1603-4b1b-b842-0d9bd55f2db1
646862c4-3dff-40a7-a35b-acc420967e7d
5b43d8e0-7c2a-42a6-83ff-0be0b501f149
5f35a319-0f48-43b2-8a31-4dcfcd250d7c
3ed9f2ed-b50f-4b8d-b797-a0345429a3d2
c37036e7-5220-42f4-89c0-c046acfd82ca
09df90ce-8715-49c4-bb60-0b7284a58cb0

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)

7765379e-cfdb-11f0-b910-4cf95d479851
77653802-cfdb-11f0-b910-4cf95d479851
77653866-cfdb-11f0-b910-4cf95d479851
776538c0-cfdb-11f0-b910-4cf95d479851
77653924-cfdb-11f0-b910-4cf95d479851
7765397e-cfdb-11f0-b910-4cf95d479851
776539d8-cfdb-11f0-b910-4cf95d479851
77653a3c-cfdb-11f0-b910-4cf95d479851
77653aa0-cfdb-11f0-b910-4cf95d479851
77653afa-cfdb-11f0-b910-4cf95d479851
77653b54-cfdb-11f0-b910-4cf95d479851
77653bb8-cfdb-11f0-b910-4cf95d479851
77653c12-cfdb-11f0-b910-4cf95d479851
77653c6c-cfdb-11f0-b910-4cf95d479851
77653cda-cfdb-11f0-b910-4cf95d479851

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)

a4a7a30f-0400-8115-87e9-5ce32bd83b97
a69da40f-0400-8115-87e9-5ce32bd83b97
5272a50f-0400-8115-87e9-5ce32bd83b97
c0e0a60f-0400-8115-87e9-5ce32bd83b97
d16da70f-0400-8115-87e9-5ce32bd83b97
482ca80f-0400-8115-87e9-5ce32bd83b97
55dfa90f-0400-8115-87e9-5ce32bd83b97
e826ab0f-0400-8115-87e9-5ce32bd83b97
8f4bac0f-0400-8115-87e9-5ce32bd83b97
9fe8ad0f-0400-8115-87e9-5ce32bd83b97
103bae0f-0400-8115-87e9-5ce32bd83b97
48b7af0f-0400-8115-87e9-5ce32bd83b97
82efb00f-0400-8115-87e9-5ce32bd83b97
1981b10f-0400-8115-87e9-5ce32bd83b97
52bdb20f-0400-8115-87e9-5ce32bd83b97

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: