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)

019fb805-0a49-7f23-9bca-19b461dd0b73
019fb805-0a4a-7182-8351-11f3aeba19ef
019fb805-0a4a-730b-b236-782a76f77439
019fb805-0a4a-745b-9a27-735b560c10ef
019fb805-0a4a-75a6-86a1-a11597e7b683
019fb805-0a4a-76f2-b971-6369acc6287b
019fb805-0a4a-7815-90a3-289f251798dd
019fb805-0a4a-7961-bb7c-cc1107e53628
019fb805-0a4a-7aa0-a7be-9a33e1950004
019fb805-0a4a-7be8-9170-3fef9f24faf6
019fb805-0a4a-7d30-861c-0a45b70c847d
019fb805-0a4a-7e77-a627-0e4bdffbe426
019fb805-0a4a-7fbb-a6fd-5bdbb75124c1
019fb805-0a4b-70fe-9b60-5b52bbede6db
019fb805-0a4b-723e-abb0-1461105dc26c

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)

1f18cd65-8635-6cd2-bba8-4cf95d479851
1f18cd65-8635-6fac-bba8-4cf95d479851
1f18cd65-8636-6150-bba8-4cf95d479851
1f18cd65-8636-62cc-bba8-4cf95d479851
1f18cd65-8636-643e-bba8-4cf95d479851
1f18cd65-8636-65b0-bba8-4cf95d479851
1f18cd65-8636-6718-bba8-4cf95d479851
1f18cd65-8636-688a-bba8-4cf95d479851
1f18cd65-8636-6a06-bba8-4cf95d479851
1f18cd65-8636-6b78-bba8-4cf95d479851
1f18cd65-8636-6d8a-bba8-4cf95d479851
1f18cd65-8636-6f10-bba8-4cf95d479851
1f18cd65-8637-6078-bba8-4cf95d479851
1f18cd65-8637-61ea-bba8-4cf95d479851
1f18cd65-8637-6352-bba8-4cf95d479851

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)

586374d8-8cd6-11f1-bba8-4cf95d479851
58637578-8cd6-11f1-bba8-4cf95d479851
58637618-8cd6-11f1-bba8-4cf95d479851
586376c2-8cd6-11f1-bba8-4cf95d479851
58637762-8cd6-11f1-bba8-4cf95d479851
58637802-8cd6-11f1-bba8-4cf95d479851
586378b6-8cd6-11f1-bba8-4cf95d479851
58637956-8cd6-11f1-bba8-4cf95d479851
586379f6-8cd6-11f1-bba8-4cf95d479851
58637a8c-8cd6-11f1-bba8-4cf95d479851
58637b2c-8cd6-11f1-bba8-4cf95d479851
58637bcc-8cd6-11f1-bba8-4cf95d479851
58637c62-8cd6-11f1-bba8-4cf95d479851
58637cf8-8cd6-11f1-bba8-4cf95d479851
58637da2-8cd6-11f1-bba8-4cf95d479851

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)

b0c6e62d-c902-840d-87ea-5ce32bd83b97
3d45e72d-c902-840d-87ea-5ce32bd83b97
82b9e82d-c902-840d-87ea-5ce32bd83b97
a17ee92d-c902-840d-87ea-5ce32bd83b97
f217ea2d-c902-840d-87ea-5ce32bd83b97
e4e8eb2d-c902-840d-87ea-5ce32bd83b97
3ffeec2d-c902-840d-87ea-5ce32bd83b97
040bed2d-c902-840d-87ea-5ce32bd83b97
1c42ee2d-c902-840d-87ea-5ce32bd83b97
386def2d-c902-840d-87ea-5ce32bd83b97
4642f02d-c902-840d-87ea-5ce32bd83b97
874ff12d-c902-840d-87ea-5ce32bd83b97
349ff22d-c902-840d-87ea-5ce32bd83b97
d378f32d-c902-840d-87ea-5ce32bd83b97
24f5f42d-c902-840d-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)

55d0c060-2de2-4395-9954-5359e0a14cbc
aafe3ed2-2cec-4273-97fa-e4bdc9ff2674
3a264ebe-f043-4aa2-a306-b3d83989a936
57e4b253-2623-478a-b3dd-b4389cb9ec0a
8dfc9066-0ef7-4e58-9aaf-e64a886939ea
320aa649-6f19-4803-8fe7-4f64ff15cede
d9b8dfeb-c72e-45c5-8bd3-6e5faf5b0831
433f09aa-f853-475e-b9c3-5a72798c3316
adc9b879-faeb-4053-bbd2-9ecbddea5007
fd1c7dcc-e3e4-4755-99dd-d2b6debfd9a7
cc65d12b-dbc9-453d-927c-261235a194ca
70a81fc0-9a1f-4dbb-ab94-3f20c8f2d0a4
4394cec4-b510-4f24-861e-08297430fdb6
79692405-d44b-4b62-b6bc-4a5acba1ff49
f394abdc-0ecf-4b46-84b7-7d0a6fe9110b

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: