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)

019f610b-de14-7e46-a9ae-66c401d44f4a
019f610b-de15-703a-b00d-9c3435b35ee3
019f610b-de15-7175-979a-4eb49c8c8a3c
019f610b-de15-7294-bb27-f3185b66a778
019f610b-de15-73aa-a020-7ee08ad88161
019f610b-de15-74c1-b246-2e687569b518
019f610b-de15-75d8-b8aa-1e92e50745a9
019f610b-de15-76ee-82af-6ae5e80f49cd
019f610b-de15-7800-8589-ffd5888258fd
019f610b-de15-7923-902d-41ca802a0218
019f610b-de15-7a36-90f8-98d88b69dff9
019f610b-de15-7b4c-b581-b67c33e25040
019f610b-de15-7c63-9960-d0ef07b361bd
019f610b-de15-7d79-9618-f837454978a7
019f610b-de15-7e8c-a863-05dda3c23564

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)

1f17f90f-3147-6da4-8199-4cf95d479851
1f17f90f-3147-6f66-8199-4cf95d479851
1f17f90f-3148-6056-8199-4cf95d479851
1f17f90f-3148-6132-8199-4cf95d479851
1f17f90f-3148-61fa-8199-4cf95d479851
1f17f90f-3148-62b8-8199-4cf95d479851
1f17f90f-3148-6380-8199-4cf95d479851
1f17f90f-3148-6448-8199-4cf95d479851
1f17f90f-3148-6506-8199-4cf95d479851
1f17f90f-3148-65ce-8199-4cf95d479851
1f17f90f-3148-670e-8199-4cf95d479851
1f17f90f-3148-67ea-8199-4cf95d479851
1f17f90f-3148-68b2-8199-4cf95d479851
1f17f90f-3148-6970-8199-4cf95d479851
1f17f90f-3148-6a2e-8199-4cf95d479851

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)

f3148b0a-7f90-11f1-8199-4cf95d479851
f3148b6e-7f90-11f1-8199-4cf95d479851
f3148bd2-7f90-11f1-8199-4cf95d479851
f3148c36-7f90-11f1-8199-4cf95d479851
f3148c9a-7f90-11f1-8199-4cf95d479851
f3148cfe-7f90-11f1-8199-4cf95d479851
f3148d62-7f90-11f1-8199-4cf95d479851
f3148dc6-7f90-11f1-8199-4cf95d479851
f3148e84-7f90-11f1-8199-4cf95d479851
f3148efc-7f90-11f1-8199-4cf95d479851
f3148f60-7f90-11f1-8199-4cf95d479851
f3148fc4-7f90-11f1-8199-4cf95d479851
f314901e-7f90-11f1-8199-4cf95d479851
f3149078-7f90-11f1-8199-4cf95d479851
f31490d2-7f90-11f1-8199-4cf95d479851

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)

51af8a0f-6a03-830c-87ea-5ce32bd83b97
a3018b0f-6a03-830c-87ea-5ce32bd83b97
74d88c0f-6a03-830c-87ea-5ce32bd83b97
9a1f8d0f-6a03-830c-87ea-5ce32bd83b97
845f8e0f-6a03-830c-87ea-5ce32bd83b97
3029900f-6a03-830c-87ea-5ce32bd83b97
945f910f-6a03-830c-87ea-5ce32bd83b97
8e8d920f-6a03-830c-87ea-5ce32bd83b97
a3dd930f-6a03-830c-87ea-5ce32bd83b97
b6b3940f-6a03-830c-87ea-5ce32bd83b97
6eaa950f-6a03-830c-87ea-5ce32bd83b97
5c33960f-6a03-830c-87ea-5ce32bd83b97
6130970f-6a03-830c-87ea-5ce32bd83b97
c5d1980f-6a03-830c-87ea-5ce32bd83b97
15a5990f-6a03-830c-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)

8cf1806c-d5b2-4649-a6b7-407151afd725
1363ecf0-10b1-4856-a80c-8fbfe663f7a1
6a3b5785-6862-41d1-b7d7-d9e95f6b44e5
f7e337b9-d3ac-4de4-86ff-00bf9f1e7a2a
974fc3d8-21b4-4f8e-ba58-5d96789f6514
ff8e6279-26d1-4ec5-ab6a-060d4b1d813e
0a3650f2-3af2-4bc4-8693-e72f6b4ab618
502abdfa-23b4-42f7-8ece-5d67970694e2
7c91f549-7985-42d7-912c-fd77b93b4b6c
cd49fec4-f7e1-420d-a8c0-bca298bebc62
3592ec9f-15da-42d8-bf45-3fff0ced2694
7671b728-f2a3-4b69-9503-4e9ec75bd06e
2d3bdb10-a32a-4f76-84e4-8eec0f092286
8c01a08f-a24b-4442-b83c-c66f2c3caa10
d1d57197-e138-4888-ad9c-b23a268c310c

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: