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)

019cd1ca-8c97-7744-97bb-e5a710489ee2
019cd1ca-8c97-79f8-b8fd-69f18a3cac15
019cd1ca-8c97-7b75-8828-6f002010ebbe
019cd1ca-8c97-7ca0-90ad-b5ce7b8fe1a2
019cd1ca-8c97-7dbf-8ced-ecfc06eb55ed
019cd1ca-8c97-7ed5-9efa-519b84b5379b
019cd1ca-8c97-7ff0-99f8-b7abc4ae3b36
019cd1ca-8c98-710b-af25-1fe9b8b837ee
019cd1ca-8c98-7225-8b4a-ec0761b28309
019cd1ca-8c98-733c-b2ab-be0ac74ca74d
019cd1ca-8c98-7457-aa05-f2c51bf44f0d
019cd1ca-8c98-756d-b948-e90c570208c4
019cd1ca-8c98-7688-8102-050330f4dabb
019cd1ca-8c98-779e-9595-5d74fa1e5d74
019cd1ca-8c98-78c9-b4b5-f3e2789298f8

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)

1f11b950-b954-6b02-bd7e-4cf95d479851
1f11b950-b954-6e90-bd7e-4cf95d479851
1f11b950-b954-6fb2-bd7e-4cf95d479851
1f11b950-b955-6084-bd7e-4cf95d479851
1f11b950-b955-6160-bd7e-4cf95d479851
1f11b950-b955-6228-bd7e-4cf95d479851
1f11b950-b955-62f0-bd7e-4cf95d479851
1f11b950-b955-63b8-bd7e-4cf95d479851
1f11b950-b955-6480-bd7e-4cf95d479851
1f11b950-b955-6548-bd7e-4cf95d479851
1f11b950-b955-6692-bd7e-4cf95d479851
1f11b950-b955-6764-bd7e-4cf95d479851
1f11b950-b955-6836-bd7e-4cf95d479851
1f11b950-b955-68fe-bd7e-4cf95d479851
1f11b950-b955-69bc-bd7e-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)

11f28830-6d97-4e4b-b2cc-e3c29f42672e
62e980dc-8de2-4abb-9d5d-696440693284
107b9dc4-ecb2-4632-956a-132d7537be8d
0cc9ca23-d20e-429c-80d1-4410cd80bfb7
269bc53f-7df7-438d-bdc5-ef10523868f9
6400c58f-210e-42d5-98ec-f1adf0b4265d
c470afd5-75e7-4bfe-997d-04d30c2164f8
ec1ea572-fd8e-4d5e-889f-b6aa25a9278c
b086c987-3901-4d74-9bc8-ee7558db5aba
f4b09055-b414-44b6-9523-19bbb601e962
608ab39e-0b4e-47ab-9a0f-f9faeded9ece
1baf11ef-37ff-4bd6-8247-8235b0a11327
97257abe-dffd-47b0-b12d-90007b4a65b5
7432be13-4bec-445b-9b3c-777d1dfba3a3
b67f7077-9578-45f1-8dff-13e2eb9aa1b2

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)

0b955eee-1b95-11f1-bd7e-4cf95d479851
0b955f5c-1b95-11f1-bd7e-4cf95d479851
0b955fb6-1b95-11f1-bd7e-4cf95d479851
0b95601a-1b95-11f1-bd7e-4cf95d479851
0b95607e-1b95-11f1-bd7e-4cf95d479851
0b9560e2-1b95-11f1-bd7e-4cf95d479851
0b95613c-1b95-11f1-bd7e-4cf95d479851
0b9561a0-1b95-11f1-bd7e-4cf95d479851
0b9561fa-1b95-11f1-bd7e-4cf95d479851
0b956254-1b95-11f1-bd7e-4cf95d479851
0b9562ae-1b95-11f1-bd7e-4cf95d479851
0b956308-1b95-11f1-bd7e-4cf95d479851
0b956362-1b95-11f1-bd7e-4cf95d479851
0b9563c6-1b95-11f1-bd7e-4cf95d479851
0b9565a6-1b95-11f1-bd7e-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)

2c7e5c26-1302-8404-87ea-5ce32bd83b97
47205d26-1302-8404-87ea-5ce32bd83b97
31905e26-1302-8404-87ea-5ce32bd83b97
c0305f26-1302-8404-87ea-5ce32bd83b97
e8af6026-1302-8404-87ea-5ce32bd83b97
51f26126-1302-8404-87ea-5ce32bd83b97
44346226-1302-8404-87ea-5ce32bd83b97
ec086326-1302-8404-87ea-5ce32bd83b97
555d6526-1302-8404-87ea-5ce32bd83b97
a0596626-1302-8404-87ea-5ce32bd83b97
c9fd6726-1302-8404-87ea-5ce32bd83b97
e7136826-1302-8404-87ea-5ce32bd83b97
d0546926-1302-8404-87ea-5ce32bd83b97
3d426a26-1302-8404-87ea-5ce32bd83b97
33eb6b26-1302-8404-87ea-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: