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)

01a0af32-0bb0-792c-a0fa-54e239c0975f
01a0af32-0bb0-7b17-86d2-ab6be99ef5a6
01a0af32-0bb0-7c57-b4e2-8f063d802b1d
01a0af32-0bb0-7d75-ab62-ef5af07c0d96
01a0af32-0bb0-7e8c-ab55-658c3e7d98ea
01a0af32-0bb0-7f9e-9241-dfc9aeca55e1
01a0af32-0bb1-70b1-b63e-27d817da867f
01a0af32-0bb1-71d3-8b0e-b7c1a47d91c1
01a0af32-0bb1-72ea-b3c6-ebea00900bf1
01a0af32-0bb1-73f4-86a9-36ccf9d879b0
01a0af32-0bb1-750b-a5d1-b3c56f02813e
01a0af32-0bb1-7621-bc23-da93112fc834
01a0af32-0bb1-7734-b631-f5addd2e321c
01a0af32-0bb1-784e-a1ec-f5895cae16ff
01a0af32-0bb1-7961-8db1-ea7d30f0c78b

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)

1f1b28da-66a0-6f84-b73e-4cf95d479851
1f1b28da-66a1-616e-b73e-4cf95d479851
1f1b28da-66a1-625e-b73e-4cf95d479851
1f1b28da-66a1-6326-b73e-4cf95d479851
1f1b28da-66a1-63ee-b73e-4cf95d479851
1f1b28da-66a1-64c0-b73e-4cf95d479851
1f1b28da-66a1-6588-b73e-4cf95d479851
1f1b28da-66a1-6650-b73e-4cf95d479851
1f1b28da-66a1-6718-b73e-4cf95d479851
1f1b28da-66a1-67e0-b73e-4cf95d479851
1f1b28da-66a1-6934-b73e-4cf95d479851
1f1b28da-66a1-6a06-b73e-4cf95d479851
1f1b28da-66a1-6ace-b73e-4cf95d479851
1f1b28da-66a1-6ba0-b73e-4cf95d479851
1f1b28da-66a1-6c68-b73e-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)

a66a1d44-b28d-11f1-b73e-4cf95d479851
a66a1da8-b28d-11f1-b73e-4cf95d479851
a66a1e0c-b28d-11f1-b73e-4cf95d479851
a66a1e7a-b28d-11f1-b73e-4cf95d479851
a66a1ede-b28d-11f1-b73e-4cf95d479851
a66a1f42-b28d-11f1-b73e-4cf95d479851
a66a1fa6-b28d-11f1-b73e-4cf95d479851
a66a2014-b28d-11f1-b73e-4cf95d479851
a66a206e-b28d-11f1-b73e-4cf95d479851
a66a20d2-b28d-11f1-b73e-4cf95d479851
a66a212c-b28d-11f1-b73e-4cf95d479851
a66a2190-b28d-11f1-b73e-4cf95d479851
a66a21f4-b28d-11f1-b73e-4cf95d479851
a66a2258-b28d-11f1-b73e-4cf95d479851
a66a22bc-b28d-11f1-b73e-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)

c49dba07-c502-8410-87ea-5ce32bd83b97
46f7bb07-c502-8410-87ea-5ce32bd83b97
4f69bc07-c502-8410-87ea-5ce32bd83b97
4b23bd07-c502-8410-87ea-5ce32bd83b97
7af8be07-c502-8410-87ea-5ce32bd83b97
6284bf07-c502-8410-87ea-5ce32bd83b97
cab8c007-c502-8410-87ea-5ce32bd83b97
0f53c107-c502-8410-87ea-5ce32bd83b97
bbd0c307-c502-8410-87ea-5ce32bd83b97
853cc407-c502-8410-87ea-5ce32bd83b97
b69cc507-c502-8410-87ea-5ce32bd83b97
5908c607-c502-8410-87ea-5ce32bd83b97
11dcc707-c502-8410-87ea-5ce32bd83b97
d7d4c807-c502-8410-87ea-5ce32bd83b97
7735c907-c502-8410-87ea-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)

470c5ab7-9118-41a9-9996-9347a7a0b5c7
0fb2dc79-7bfc-412a-8b12-68ee4c6844b4
dfe6e60b-5ac9-4e13-8514-4f0a23d4d095
7403cbfb-0022-477e-a53a-82415b40bddd
bb9695fe-2e01-4a4c-b14b-be209bc4392e
6fd57de3-2ebc-4a1d-aa76-ca3d30d00ec5
3499e641-7f04-4127-8409-16befc14c95f
32463ce3-8c78-4566-9725-d25069591593
9128b033-ec72-4cd4-ad3d-ac607f935fb3
343eed62-70cf-4e72-a935-4976e32965ef
436ffac5-7533-4213-a466-15bf12b95ce6
070357c5-2e74-4ec7-b622-f4d7a6d3aadf
227f6461-44db-45ae-8545-10d1093428ad
d9f43702-1c25-4b00-aa54-9e99135dd135
c0dcacf5-bb70-4f82-921e-f163dce3ca93

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: