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)

019d7350-c767-73bb-956b-026de02b41f7
019d7350-c767-75a6-a1ce-5daf46060ab8
019d7350-c767-76ea-881f-593d87060fea
019d7350-c767-7809-8db4-10469cc658fa
019d7350-c767-7927-808f-a61fdf4c28e1
019d7350-c767-7a46-8a63-c70b90ef3f82
019d7350-c767-7b5d-96c6-701d7d731004
019d7350-c767-7c77-b9e4-9243c763f720
019d7350-c767-7d92-b5ea-c5153ec21a83
019d7350-c767-7ead-b4d2-7c9e9ad7bd78
019d7350-c767-7fc7-9e78-6cc5b152b61a
019d7350-c768-70e6-b721-2cff7118dcc7
019d7350-c768-7205-8ab4-d984d8a9ab98
019d7350-c768-7350-8d5f-3a52df77f114
019d7350-c768-746b-8ddb-0355136c4076

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)

1f1343a9-6ee9-6eca-8963-4cf95d479851
1f1343a9-6eea-605a-8963-4cf95d479851
1f1343a9-6eea-6136-8963-4cf95d479851
1f1343a9-6eea-61fe-8963-4cf95d479851
1f1343a9-6eea-62bc-8963-4cf95d479851
1f1343a9-6eea-6384-8963-4cf95d479851
1f1343a9-6eea-644c-8963-4cf95d479851
1f1343a9-6eea-650a-8963-4cf95d479851
1f1343a9-6eea-65c8-8963-4cf95d479851
1f1343a9-6eea-6686-8963-4cf95d479851
1f1343a9-6eea-67b2-8963-4cf95d479851
1f1343a9-6eea-687a-8963-4cf95d479851
1f1343a9-6eea-6938-8963-4cf95d479851
1f1343a9-6eea-6a0a-8963-4cf95d479851
1f1343a9-6eea-6ad2-8963-4cf95d479851

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)

720680f5-32ed-4de6-bb0f-e7015326be42
06d3d98a-620f-4688-ad5e-5ed69185f82c
1af32ff0-6f64-49df-881c-cb985c65b4eb
0180d8a0-f242-4e85-b3a8-0a3efbad6126
0868de48-1af6-4fa5-b469-1f7ffa64f075
1134b7e4-470b-4f4f-a5cd-c3ab42dbe0f4
af1d70e0-bc29-4418-aeb0-6ed34ddf34b6
ccee292c-84fa-4af9-862e-a299990b2308
1bc2d9f6-315c-471d-bad6-6de051093ca2
220a0bfa-4cb5-4e1c-ab75-6c1dfd37b6f1
f9b66ef6-1c1d-42e0-ad42-7c74e5ebec58
1cdab98f-ec11-4897-9fb4-beb92cb34e00
1da8ffbf-02dd-4552-9d46-9b145282b603
9addb219-baee-4f8c-826b-ff55355b0422
2322f6bd-d484-4938-9d69-c93eba470d7a

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)

96eeafe6-343a-11f1-8963-4cf95d479851
96eeb04a-343a-11f1-8963-4cf95d479851
96eeb0b8-343a-11f1-8963-4cf95d479851
96eeb126-343a-11f1-8963-4cf95d479851
96eeb18a-343a-11f1-8963-4cf95d479851
96eeb1f8-343a-11f1-8963-4cf95d479851
96eeb25c-343a-11f1-8963-4cf95d479851
96eeb2b6-343a-11f1-8963-4cf95d479851
96eeb31a-343a-11f1-8963-4cf95d479851
96eeb37e-343a-11f1-8963-4cf95d479851
96eeb3e2-343a-11f1-8963-4cf95d479851
96eeb446-343a-11f1-8963-4cf95d479851
96eeb4a0-343a-11f1-8963-4cf95d479851
96eeb504-343a-11f1-8963-4cf95d479851
96eeb55e-343a-11f1-8963-4cf95d479851

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)

db560407-2104-8306-87ea-5ce32bd83b97
291e0507-2104-8306-87ea-5ce32bd83b97
8abf0607-2104-8306-87ea-5ce32bd83b97
aff50707-2104-8306-87ea-5ce32bd83b97
803d0807-2104-8306-87ea-5ce32bd83b97
c2580907-2104-8306-87ea-5ce32bd83b97
59bc0a07-2104-8306-87ea-5ce32bd83b97
a8ec0b07-2104-8306-87ea-5ce32bd83b97
d58b0d07-2104-8306-87ea-5ce32bd83b97
fb8f0e07-2104-8306-87ea-5ce32bd83b97
25330f07-2104-8306-87ea-5ce32bd83b97
b05f1007-2104-8306-87ea-5ce32bd83b97
77df1107-2104-8306-87ea-5ce32bd83b97
31001207-2104-8306-87ea-5ce32bd83b97
25911307-2104-8306-87ea-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

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: