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)

019c0b07-5fe3-7dcb-8fc5-a4f5f5c95c7c
019c0b07-5fe3-7f54-ac2c-baf55365a695
019c0b07-5fe4-7094-98d9-4b6be3209089
019c0b07-5fe4-71bb-8111-658dbbb61451
019c0b07-5fe4-72da-a541-9d558c67a483
019c0b07-5fe4-73f4-ba9d-e9e348255b59
019c0b07-5fe4-7513-bac4-a1da6052852d
019c0b07-5fe4-762e-835d-faa55c00dfd4
019c0b07-5fe4-774c-ac72-ab52eb4ad0c9
019c0b07-5fe4-7832-80d6-747e7950f003
019c0b07-5fe4-7950-8472-b0f041d475ad
019c0b07-5fe4-7a6b-97d7-41a5f9449873
019c0b07-5fe4-7b86-aa0c-5b1e69babe19
019c0b07-5fe4-7ca0-a577-298395f19d7e
019c0b07-5fe4-7dbb-8dad-b5c2b58ddbef

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)

1f0fd40e-3931-6fc0-85ea-4cf95d479851
1f0fd40e-3932-6146-85ea-4cf95d479851
1f0fd40e-3932-622c-85ea-4cf95d479851
1f0fd40e-3932-6308-85ea-4cf95d479851
1f0fd40e-3932-63d0-85ea-4cf95d479851
1f0fd40e-3932-6498-85ea-4cf95d479851
1f0fd40e-3932-656a-85ea-4cf95d479851
1f0fd40e-3932-6628-85ea-4cf95d479851
1f0fd40e-3932-66fa-85ea-4cf95d479851
1f0fd40e-3932-67b8-85ea-4cf95d479851
1f0fd40e-3932-6902-85ea-4cf95d479851
1f0fd40e-3932-69d4-85ea-4cf95d479851
1f0fd40e-3932-6aa6-85ea-4cf95d479851
1f0fd40e-3932-6b64-85ea-4cf95d479851
1f0fd40e-3932-6c2c-85ea-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)

c3a7a185-92ad-4c41-be52-bc66d221ab8f
410545d6-7e74-4998-a6f7-ae7586d78f5f
a370a30e-2678-4e7e-b931-02759781b776
7df9560d-42e2-4c47-b5e3-47938d1fee6e
322c6a46-b989-4d0c-90e2-0f2e76c66c83
a71fe04f-2ef3-45d0-89ee-878caaef525d
890a4ed4-418f-44c5-b330-1c6c870c9065
7a38fa5e-d582-4c41-92e1-5204f4060b4b
02815f76-8173-4eb0-8f71-cb6e738629ef
a0ec77e9-dbe6-4e57-9c7e-5194849584d3
2d0fafcf-3804-4a18-8649-00d0bd1ad95c
570cf4b8-e6f5-4d7b-842e-ff81135ca977
ddf295bc-9334-4862-a5e0-88dce268e52c
b2c306d2-2cc3-42d9-bb46-e2a69322f4e5
54ee18d9-873a-4409-8923-214bed0bafd7

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)

e393314a-fd40-11f0-85ea-4cf95d479851
e39331ae-fd40-11f0-85ea-4cf95d479851
e3933208-fd40-11f0-85ea-4cf95d479851
e393326c-fd40-11f0-85ea-4cf95d479851
e39332c6-fd40-11f0-85ea-4cf95d479851
e393332a-fd40-11f0-85ea-4cf95d479851
e3933384-fd40-11f0-85ea-4cf95d479851
e39333e8-fd40-11f0-85ea-4cf95d479851
e3933442-fd40-11f0-85ea-4cf95d479851
e39334ba-fd40-11f0-85ea-4cf95d479851
e3933514-fd40-11f0-85ea-4cf95d479851
e3933578-fd40-11f0-85ea-4cf95d479851
e39335d2-fd40-11f0-85ea-4cf95d479851
e3933636-fd40-11f0-85ea-4cf95d479851
e39336a4-fd40-11f0-85ea-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)

182aa126-5904-8d01-87ea-5ce32bd83b97
b7d9a226-5904-8d01-87ea-5ce32bd83b97
8d23a326-5904-8d01-87ea-5ce32bd83b97
a8f2a426-5904-8d01-87ea-5ce32bd83b97
763da526-5904-8d01-87ea-5ce32bd83b97
9691a626-5904-8d01-87ea-5ce32bd83b97
6dd8a726-5904-8d01-87ea-5ce32bd83b97
ea04a826-5904-8d01-87ea-5ce32bd83b97
6c09a926-5904-8d01-87ea-5ce32bd83b97
38faaa26-5904-8d01-87ea-5ce32bd83b97
9ec5ab26-5904-8d01-87ea-5ce32bd83b97
a8e4ac26-5904-8d01-87ea-5ce32bd83b97
3689ad26-5904-8d01-87ea-5ce32bd83b97
4afdae26-5904-8d01-87ea-5ce32bd83b97
7479af26-5904-8d01-87ea-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

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: