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)

01a1e004-6d40-7d9e-834a-6f78078b650f
01a1e004-6d40-7f30-9f9e-c4c67739940d
01a1e004-6d41-70fa-a223-9a4bd02c681a
01a1e004-6d41-7219-94b9-d41f947394fa
01a1e004-6d41-7392-bbe4-0c6d0ec072de
01a1e004-6d41-74e2-b980-308fcc975741
01a1e004-6d41-75f8-a4ae-e8c1d3d4b788
01a1e004-6d41-770b-b064-25474067e43a
01a1e004-6d41-781d-a187-d0bfe74e1c1d
01a1e004-6d41-7930-a8e7-6755d6288bd5
01a1e004-6d41-7a42-96ba-e420b9bc6589
01a1e004-6d41-7b96-8cbb-d77e5847616a
01a1e004-6d41-7cb1-ad85-ef7423fcbb9e
01a1e004-6d41-7dc7-8cb6-68737497ec31
01a1e004-6d41-7ee6-8da6-fb219e697cbd

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)

1f1e110c-06d2-63b0-a94a-4cf95d479851
1f1e110c-06d2-657c-a94a-4cf95d479851
1f1e110c-06d2-666c-a94a-4cf95d479851
1f1e110c-06d2-673e-a94a-4cf95d479851
1f1e110c-06d2-6806-a94a-4cf95d479851
1f1e110c-06d2-68ce-a94a-4cf95d479851
1f1e110c-06d2-6996-a94a-4cf95d479851
1f1e110c-06d2-6a54-a94a-4cf95d479851
1f1e110c-06d2-6b1c-a94a-4cf95d479851
1f1e110c-06d2-6bda-a94a-4cf95d479851
1f1e110c-06d2-6d56-a94a-4cf95d479851
1f1e110c-06d2-6e28-a94a-4cf95d479851
1f1e110c-06d2-6ee6-a94a-4cf95d479851
1f1e110c-06d2-6fae-a94a-4cf95d479851
1f1e110c-06d3-6076-a94a-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)

c06d315c-e110-11f1-a94a-4cf95d479851
c06d31c0-e110-11f1-a94a-4cf95d479851
c06d321a-e110-11f1-a94a-4cf95d479851
c06d3288-e110-11f1-a94a-4cf95d479851
c06d32e2-e110-11f1-a94a-4cf95d479851
c06d3346-e110-11f1-a94a-4cf95d479851
c06d34ae-e110-11f1-a94a-4cf95d479851
c06d351c-e110-11f1-a94a-4cf95d479851
c06d3580-e110-11f1-a94a-4cf95d479851
c06d35e4-e110-11f1-a94a-4cf95d479851
c06d3652-e110-11f1-a94a-4cf95d479851
c06d36c0-e110-11f1-a94a-4cf95d479851
c06d372e-e110-11f1-a94a-4cf95d479851
c06d3792-e110-11f1-a94a-4cf95d479851
c06d37f6-e110-11f1-a94a-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)

2c9ded1c-d703-8f13-87ea-5ce32bd83b97
16c1ee1c-d703-8f13-87ea-5ce32bd83b97
9aaeef1c-d703-8f13-87ea-5ce32bd83b97
ca33f01c-d703-8f13-87ea-5ce32bd83b97
0d0df21c-d703-8f13-87ea-5ce32bd83b97
7708f31c-d703-8f13-87ea-5ce32bd83b97
33dff41c-d703-8f13-87ea-5ce32bd83b97
11fdf51c-d703-8f13-87ea-5ce32bd83b97
76f5f61c-d703-8f13-87ea-5ce32bd83b97
d1b0f71c-d703-8f13-87ea-5ce32bd83b97
958bf81c-d703-8f13-87ea-5ce32bd83b97
195bf91c-d703-8f13-87ea-5ce32bd83b97
197bfa1c-d703-8f13-87ea-5ce32bd83b97
dbbafb1c-d703-8f13-87ea-5ce32bd83b97
0b13fc1c-d703-8f13-87ea-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)

f0d964fb-b9d3-40ba-854e-458374b055e9
a8eb962c-70d3-4947-a1ff-165d019a3c36
51bdf779-361d-45f1-b727-460347b36514
0aa7b96b-f602-4735-8cb8-c77e9e084f2b
bc1a381c-b838-47de-ac2d-8337fdef49ac
d68be00d-4447-4cc9-8757-25960a6e649a
e75c0c2b-5e23-4bc5-8a47-8d68d3fb18de
d744ea79-cbb3-4d3b-90ff-174d45210c63
72cfa75e-f16c-4c70-a44a-6884815fd084
4803476a-6ff4-49fa-a02e-d3e30d970347
d6bfadc6-1a56-4cbd-ae77-4e5cc48b6aa4
cd550e04-4aa7-4db7-ba2f-041b4b779340
4bd00992-d62a-41ae-9f17-bbabf38bcef7
987aad43-54a9-4e85-ac1d-27ff98d4dafb
62fac023-a8f3-4bf5-bf4e-514c18d5f8e3

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: