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)

019abe9e-c482-71d8-ad94-62f61dff6777
019abe9e-c482-7365-897e-a0b6de4a570b
019abe9e-c482-74ad-8541-309715e6aba5
019abe9e-c482-75cf-8e5f-3c3d0c05d9ec
019abe9e-c482-76ee-b3c7-0a96020b5409
019abe9e-c482-7809-8e30-93553e69861e
019abe9e-c482-78b5-8c3c-0aaa4ecff5ae
019abe9e-c482-79d8-889a-ccd267d4c652
019abe9e-c482-7af2-ae96-c7b299319ebf
019abe9e-c482-7c0d-9508-d9bbbea2a46f
019abe9e-c482-7d2c-aff9-ae1f90bac414
019abe9e-c482-7e46-a60b-ce9e43b5c36d
019abe9e-c482-7f61-845b-ae8c5e04ef82
019abe9e-c483-7094-954e-8b20a29be7dd
019abe9e-c483-71d3-9b78-1ff5e4a05233

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)

1f0ca882-d5d8-6582-9e9b-4cf95d479851
1f0ca882-d5d8-671c-9e9b-4cf95d479851
1f0ca882-d5d8-680c-9e9b-4cf95d479851
1f0ca882-d5d8-68de-9e9b-4cf95d479851
1f0ca882-d5d8-69b0-9e9b-4cf95d479851
1f0ca882-d5d8-6a78-9e9b-4cf95d479851
1f0ca882-d5d8-6b40-9e9b-4cf95d479851
1f0ca882-d5d8-6c08-9e9b-4cf95d479851
1f0ca882-d5d8-6cc6-9e9b-4cf95d479851
1f0ca882-d5d8-6d8e-9e9b-4cf95d479851
1f0ca882-d5d8-6ee2-9e9b-4cf95d479851
1f0ca882-d5d8-6fb4-9e9b-4cf95d479851
1f0ca882-d5d9-6072-9e9b-4cf95d479851
1f0ca882-d5d9-613a-9e9b-4cf95d479851
1f0ca882-d5d9-61f8-9e9b-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)

69d76e82-d3e3-4d23-896b-52f21f8b4dc4
146452e4-9347-431f-8e16-b9f59244773d
640f1af8-654f-4c21-bf1f-eb6d3328b526
d8d838e9-876f-45ed-9c0a-a8e2d5cbdf4f
0fec716a-334b-4184-a282-b656b561dc2f
e78a20c4-736e-4ebc-9d3c-1fa00229e794
9cada0b0-1f44-4309-87b3-91850d8683fd
552d6107-a5ad-42ef-9585-581ab2471212
7868602d-ae9a-4a2d-810b-d421fe3bad21
d7930d00-4f27-464f-8f5c-e7289dc53135
7da5166d-11e5-4c2f-98da-d02867a241c5
00102bac-4ab0-4fbe-811a-b4d5d9443edb
7c39773d-57e2-40fb-8614-1fdd00c756b3
4bcb6461-451b-4f83-ba55-b0c4e7aa0ce8
bcc17df5-92dc-437a-95b3-6c3543a1182f

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)

2d5d972a-ca88-11f0-9e9b-4cf95d479851
2d5d978e-ca88-11f0-9e9b-4cf95d479851
2d5d97fc-ca88-11f0-9e9b-4cf95d479851
2d5d9856-ca88-11f0-9e9b-4cf95d479851
2d5d98ba-ca88-11f0-9e9b-4cf95d479851
2d5d9928-ca88-11f0-9e9b-4cf95d479851
2d5d9996-ca88-11f0-9e9b-4cf95d479851
2d5d99f0-ca88-11f0-9e9b-4cf95d479851
2d5d9a5e-ca88-11f0-9e9b-4cf95d479851
2d5d9ac2-ca88-11f0-9e9b-4cf95d479851
2d5d9b26-ca88-11f0-9e9b-4cf95d479851
2d5d9b80-ca88-11f0-9e9b-4cf95d479851
2d5d9be4-ca88-11f0-9e9b-4cf95d479851
2d5d9c48-ca88-11f0-9e9b-4cf95d479851
2d5d9ca2-ca88-11f0-9e9b-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)

f3d2651b-4501-8a14-87e9-5ce32bd83b97
2bc3661b-4501-8a14-87e9-5ce32bd83b97
5eb2671b-4501-8a14-87e9-5ce32bd83b97
54d9681b-4501-8a14-87e9-5ce32bd83b97
497d691b-4501-8a14-87e9-5ce32bd83b97
71ac6a1b-4501-8a14-87e9-5ce32bd83b97
a8d06b1b-4501-8a14-87e9-5ce32bd83b97
e66c6c1b-4501-8a14-87e9-5ce32bd83b97
9ac36d1b-4501-8a14-87e9-5ce32bd83b97
96f56e1b-4501-8a14-87e9-5ce32bd83b97
43d86f1b-4501-8a14-87e9-5ce32bd83b97
b71c701b-4501-8a14-87e9-5ce32bd83b97
bf54711b-4501-8a14-87e9-5ce32bd83b97
9562721b-4501-8a14-87e9-5ce32bd83b97
bedf731b-4501-8a14-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: