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)

019f4589-f40b-7cc5-9c28-254223bbaec4
019f4589-f40b-7e63-bd51-89aa2b4b5db8
019f4589-f40b-7fa2-acbe-c09955a70b26
019f4589-f40c-70c9-b4c5-d4c96feba8c9
019f4589-f40c-71e0-be69-b358237cb38e
019f4589-f40c-72f2-a240-1a85edee5616
019f4589-f40c-7409-89f9-559fdf6278f0
019f4589-f40c-751b-8f0f-7f3e61980b00
019f4589-f40c-762e-826b-b742e88a3ce0
019f4589-f40c-7744-b25b-29e94a3a62a6
019f4589-f40c-785b-85c7-222fa34e69e2
019f4589-f40c-796d-8f64-e49d1d76b891
019f4589-f40c-7a7f-b444-d35ad5c22863
019f4589-f40c-7b92-892b-0e8154d28a86
019f4589-f40c-7ca4-a82d-5af634085ad9

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)

1f17b5e7-04e7-690a-90cd-4cf95d479851
1f17b5e7-04e7-6ad6-90cd-4cf95d479851
1f17b5e7-04e7-6bb2-90cd-4cf95d479851
1f17b5e7-04e7-6c7a-90cd-4cf95d479851
1f17b5e7-04e7-6d42-90cd-4cf95d479851
1f17b5e7-04e7-6e00-90cd-4cf95d479851
1f17b5e7-04e7-6ebe-90cd-4cf95d479851
1f17b5e7-04e7-6f7c-90cd-4cf95d479851
1f17b5e7-04e8-603a-90cd-4cf95d479851
1f17b5e7-04e8-60f8-90cd-4cf95d479851
1f17b5e7-04e8-6256-90cd-4cf95d479851
1f17b5e7-04e8-6328-90cd-4cf95d479851
1f17b5e7-04e8-63e6-90cd-4cf95d479851
1f17b5e7-04e8-64a4-90cd-4cf95d479851
1f17b5e7-04e8-6562-90cd-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)

704e8634-7b5e-11f1-90cd-4cf95d479851
704e8698-7b5e-11f1-90cd-4cf95d479851
704e8706-7b5e-11f1-90cd-4cf95d479851
704e876a-7b5e-11f1-90cd-4cf95d479851
704e87d8-7b5e-11f1-90cd-4cf95d479851
704e8832-7b5e-11f1-90cd-4cf95d479851
704e8896-7b5e-11f1-90cd-4cf95d479851
704e88fa-7b5e-11f1-90cd-4cf95d479851
704e8968-7b5e-11f1-90cd-4cf95d479851
704e89cc-7b5e-11f1-90cd-4cf95d479851
704e8a30-7b5e-11f1-90cd-4cf95d479851
704e8a9e-7b5e-11f1-90cd-4cf95d479851
704e8b0c-7b5e-11f1-90cd-4cf95d479851
704e8b70-7b5e-11f1-90cd-4cf95d479851
704e8bd4-7b5e-11f1-90cd-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)

858aa724-7e01-8e0b-87ea-5ce32bd83b97
0a0fa824-7e01-8e0b-87ea-5ce32bd83b97
edf5a924-7e01-8e0b-87ea-5ce32bd83b97
63a8aa24-7e01-8e0b-87ea-5ce32bd83b97
91afab24-7e01-8e0b-87ea-5ce32bd83b97
7a67ac24-7e01-8e0b-87ea-5ce32bd83b97
5818ad24-7e01-8e0b-87ea-5ce32bd83b97
9505ae24-7e01-8e0b-87ea-5ce32bd83b97
99c2af24-7e01-8e0b-87ea-5ce32bd83b97
9efbb024-7e01-8e0b-87ea-5ce32bd83b97
36cdb124-7e01-8e0b-87ea-5ce32bd83b97
23f4b224-7e01-8e0b-87ea-5ce32bd83b97
535bb324-7e01-8e0b-87ea-5ce32bd83b97
b08ab424-7e01-8e0b-87ea-5ce32bd83b97
9599b524-7e01-8e0b-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)

316cc781-d60b-410a-80a4-c49c58633a27
b4ac796f-9d0e-4b5f-948a-8c7fd2c075d4
27dcd034-4c9b-402b-9c8b-25655fd61f37
55035847-6f57-4383-a942-9b8049e1a1b0
9c3b6575-2955-43c7-be91-3593cc170684
42463501-db64-43a0-ba8b-07bf75cbb947
d810745b-a860-47e8-8608-d977192e8349
15d8e1f1-b432-498c-bfb3-a1fadbcfed80
f166a04d-0459-4080-a8c4-a490fbba0678
3809deb6-ce42-4257-ae41-6c64b10dc83a
c404751b-883b-4995-953f-a856c27d7b59
75c75968-ea86-44d3-a7c1-855cc591618f
e2f6945b-8e1d-41af-a350-44e9e04374db
02c35afc-19d4-43eb-a3c4-c67d159396d9
5b623526-44d0-4669-9324-50992f114f11

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: