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)

019f1b3c-9a41-7307-9335-0db83080e796
019f1b3c-9a41-74ad-b30e-1ef6008fa9be
019f1b3c-9a41-75e8-9c50-7acb6f06b1c5
019f1b3c-9a41-7703-98f6-df13b0339c8c
019f1b3c-9a41-7815-9f8e-04985c69d4f7
019f1b3c-9a41-792c-bf77-0751e2629721
019f1b3c-9a41-7a42-8e8a-fe5cf9aa33be
019f1b3c-9a41-7b59-9c85-bf7199a05ce1
019f1b3c-9a41-7c6b-a31f-8c65b088293e
019f1b3c-9a41-7d82-a6bf-4475bba6299d
019f1b3c-9a41-7e94-9aa8-0d7513203955
019f1b3c-9a41-7faa-8f90-0f4d2535ab7d
019f1b3c-9a42-70bd-98f9-45446020a2df
019f1b3c-9a42-71d3-ad0e-54622facaeb6
019f1b3c-9a42-72ea-bbed-d9c7dd2d3752

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)

1f174ea0-2caf-6fae-a13b-4cf95d479851
1f174ea0-2cb0-6198-a13b-4cf95d479851
1f174ea0-2cb0-627e-a13b-4cf95d479851
1f174ea0-2cb0-6350-a13b-4cf95d479851
1f174ea0-2cb0-6418-a13b-4cf95d479851
1f174ea0-2cb0-653a-a13b-4cf95d479851
1f174ea0-2cb0-6620-a13b-4cf95d479851
1f174ea0-2cb0-6706-a13b-4cf95d479851
1f174ea0-2cb0-67ce-a13b-4cf95d479851
1f174ea0-2cb0-688c-a13b-4cf95d479851
1f174ea0-2cb0-69fe-a13b-4cf95d479851
1f174ea0-2cb0-6ac6-a13b-4cf95d479851
1f174ea0-2cb0-6b8e-a13b-4cf95d479851
1f174ea0-2cb0-6c56-a13b-4cf95d479851
1f174ea0-2cb0-6d1e-a13b-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)

02cb0df0-74ea-11f1-a13b-4cf95d479851
02cb0e4a-74ea-11f1-a13b-4cf95d479851
02cb0eb8-74ea-11f1-a13b-4cf95d479851
02cb0f12-74ea-11f1-a13b-4cf95d479851
02cb0f80-74ea-11f1-a13b-4cf95d479851
02cb0fe4-74ea-11f1-a13b-4cf95d479851
02cb103e-74ea-11f1-a13b-4cf95d479851
02cb10a2-74ea-11f1-a13b-4cf95d479851
02cb1110-74ea-11f1-a13b-4cf95d479851
02cb117e-74ea-11f1-a13b-4cf95d479851
02cb11e2-74ea-11f1-a13b-4cf95d479851
02cb1246-74ea-11f1-a13b-4cf95d479851
02cb12aa-74ea-11f1-a13b-4cf95d479851
02cb130e-74ea-11f1-a13b-4cf95d479851
02cb1386-74ea-11f1-a13b-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)

c0225204-4a00-860b-87ea-5ce32bd83b97
eb735304-4a00-860b-87ea-5ce32bd83b97
42f25404-4a00-860b-87ea-5ce32bd83b97
5a705604-4a00-860b-87ea-5ce32bd83b97
ff935704-4a00-860b-87ea-5ce32bd83b97
f3e05804-4a00-860b-87ea-5ce32bd83b97
52455904-4a00-860b-87ea-5ce32bd83b97
e8e55a04-4a00-860b-87ea-5ce32bd83b97
03c45b04-4a00-860b-87ea-5ce32bd83b97
c09d5c04-4a00-860b-87ea-5ce32bd83b97
9f9d5d04-4a00-860b-87ea-5ce32bd83b97
a07b5e04-4a00-860b-87ea-5ce32bd83b97
9c655f04-4a00-860b-87ea-5ce32bd83b97
d8be6004-4a00-860b-87ea-5ce32bd83b97
3ca26104-4a00-860b-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)

9a94225b-03db-4ea2-abec-77bc7a46c68d
f08c8c9e-80e4-4b02-90e1-4d342b6767df
59c6b51d-2bfd-4078-b14c-da15eeb4e5f8
8b12401f-05ae-499f-96c5-01616e633915
f9e441d6-2816-4fee-b08f-7abc1fe835e3
0e34d676-306d-4100-80a9-9e8a101b0f56
a63b948a-2ba8-4301-9a06-203d29a7c6e9
228405a4-99e2-4d17-91ac-0c4f7a47dd76
7ed18682-3bb6-42f0-ac94-e87aa62dc1d9
b6c57885-9b0a-472e-9c7d-4ea6794fa673
03f91d75-133e-4aed-ac18-836ee3a3ba17
659352c4-e6ab-44e6-995e-b0405d98f89e
a8838d08-d132-4539-81cf-81f64b6028bd
90b06c45-dd4d-412c-9157-a15a3697a709
909d3a79-342a-4180-a846-1e6a3ceed1c5

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: