UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019fb9f8-9de7-7c00-81f7-15e144a7f7b6
019fb9f8-9de7-7df8-9d46-636de4f5da77
019fb9f8-9de7-7f3c-8792-52a20ab14c84
019fb9f8-9de8-7057-b5b5-4eb517b29b6f
019fb9f8-9de8-716d-b327-331d3c6d54cf
019fb9f8-9de8-7284-adca-1aeec738b3f0
019fb9f8-9de8-7396-9a52-c7887ae85a6a
019fb9f8-9de8-74ad-b981-4cc9e21f6a7c
019fb9f8-9de8-75cb-97a2-9943f967d5ff
019fb9f8-9de8-76e2-8e19-cff8f9802d0b
019fb9f8-9de8-77f4-9805-b0d8ab55f7b3
019fb9f8-9de8-7907-b78e-0a3c1dc848c5
019fb9f8-9de8-7a1d-91d0-87c39b644148
019fb9f8-9de8-7b30-9d89-acd9f540b1cc
019fb9f8-9de8-7c42-9255-8f1f2af875b1

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)

1f18d229-3199-6a2a-afe9-4cf95d479851
1f18d229-3199-6be2-afe9-4cf95d479851
1f18d229-3199-6cd2-afe9-4cf95d479851
1f18d229-3199-6dae-afe9-4cf95d479851
1f18d229-3199-6e80-afe9-4cf95d479851
1f18d229-3199-6f3e-afe9-4cf95d479851
1f18d229-319a-6006-afe9-4cf95d479851
1f18d229-319a-60ce-afe9-4cf95d479851
1f18d229-319a-6196-afe9-4cf95d479851
1f18d229-319a-6254-afe9-4cf95d479851
1f18d229-319a-639e-afe9-4cf95d479851
1f18d229-319a-6470-afe9-4cf95d479851
1f18d229-319a-6538-afe9-4cf95d479851
1f18d229-319a-6614-afe9-4cf95d479851
1f18d229-319a-66dc-afe9-4cf95d479851

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)

9319a7b8-8d22-11f1-afe9-4cf95d479851
9319a826-8d22-11f1-afe9-4cf95d479851
9319a88a-8d22-11f1-afe9-4cf95d479851
9319a8f8-8d22-11f1-afe9-4cf95d479851
9319a95c-8d22-11f1-afe9-4cf95d479851
9319a9b6-8d22-11f1-afe9-4cf95d479851
9319aa1a-8d22-11f1-afe9-4cf95d479851
9319aa7e-8d22-11f1-afe9-4cf95d479851
9319aae2-8d22-11f1-afe9-4cf95d479851
9319ab46-8d22-11f1-afe9-4cf95d479851
9319abaa-8d22-11f1-afe9-4cf95d479851
9319ac0e-8d22-11f1-afe9-4cf95d479851
9319ac72-8d22-11f1-afe9-4cf95d479851
9319acd6-8d22-11f1-afe9-4cf95d479851
9319ad30-8d22-11f1-afe9-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

0ef6271a-eb04-840d-87ea-5ce32bd83b97
c9e5281a-eb04-840d-87ea-5ce32bd83b97
c733291a-eb04-840d-87ea-5ce32bd83b97
c0782a1a-eb04-840d-87ea-5ce32bd83b97
8d282b1a-eb04-840d-87ea-5ce32bd83b97
b08a2c1a-eb04-840d-87ea-5ce32bd83b97
ab0c2d1a-eb04-840d-87ea-5ce32bd83b97
ae512e1a-eb04-840d-87ea-5ce32bd83b97
74192f1a-eb04-840d-87ea-5ce32bd83b97
42d3301a-eb04-840d-87ea-5ce32bd83b97
5142321a-eb04-840d-87ea-5ce32bd83b97
e445331a-eb04-840d-87ea-5ce32bd83b97
40b3341a-eb04-840d-87ea-5ce32bd83b97
aa1f351a-eb04-840d-87ea-5ce32bd83b97
4ed3361a-eb04-840d-87ea-5ce32bd83b97

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)

4f275970-3a6d-4ba0-90d6-9e8a2feb0ff3
4a508c44-0039-4b62-a44a-efe478eb7d3a
4b0b008c-18d7-4f8c-a23e-ae70ab4bcb9b
c72ad4b8-853b-4cee-9b5c-b4e5b5e35a93
41e11a95-660b-4a52-ad54-2b8a1b1f39ec
588e7a8d-d257-4763-81f6-1582197b3a9f
a46fcedf-1a00-4656-a0bf-e0fac710a833
d3359b3b-313c-4fac-8b06-b9568bdd0440
003b969f-fa90-4821-8314-d1a4612dd733
e333b34d-59fb-4abd-ae94-f6a949bfaf4b
ab9eac37-5788-4cf1-aad8-39477a6da457
d216e50b-6713-4a08-8fc6-8f1d25140025
70c5392b-6cee-4c74-8cbe-bbd714b91695
d6a147a9-623a-4019-babe-1dbb95ca39b0
7d57c8c6-5885-406a-91a2-fa6b9b92cc31

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: