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)

019bd05b-036b-7544-964e-b8d5124159bd
019bd05b-036b-76cd-be05-6b87a9936bd4
019bd05b-036b-7809-a522-58e97c245a2e
019bd05b-036b-7927-b32c-ae34d1c0fe5e
019bd05b-036b-7a42-a75a-f7f42d3a0924
019bd05b-036b-7b59-aa1f-754ebe1bbc36
019bd05b-036b-7c6f-abcf-4aeae7a9e269
019bd05b-036b-7d86-a22a-e9615565115b
019bd05b-036b-7ea0-8708-783e7e5efc8d
019bd05b-036b-7fb3-a2d5-f9ef046bb823
019bd05b-036c-70c9-952f-845c7467a367
019bd05b-036c-71e0-b668-553218f3ec57
019bd05b-036c-72f2-a774-4f2c20e8bc92
019bd05b-036c-7409-bfec-d8c886338d4f
019bd05b-036c-751f-a0e4-c87c361b7978

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)

1f0f44cf-6b6f-6aec-872b-4cf95d479851
1f0f44cf-6b6f-6c68-872b-4cf95d479851
1f0f44cf-6b6f-6d4e-872b-4cf95d479851
1f0f44cf-6b6f-6e20-872b-4cf95d479851
1f0f44cf-6b6f-6ef2-872b-4cf95d479851
1f0f44cf-6b6f-6fba-872b-4cf95d479851
1f0f44cf-6b70-6082-872b-4cf95d479851
1f0f44cf-6b70-614a-872b-4cf95d479851
1f0f44cf-6b70-6212-872b-4cf95d479851
1f0f44cf-6b70-62d0-872b-4cf95d479851
1f0f44cf-6b70-6410-872b-4cf95d479851
1f0f44cf-6b70-64e2-872b-4cf95d479851
1f0f44cf-6b70-65aa-872b-4cf95d479851
1f0f44cf-6b70-6672-872b-4cf95d479851
1f0f44cf-6b70-6730-872b-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)

abd3c0ec-8346-4ea5-9b8a-2b5785870fe6
6720a471-8140-436f-a3fc-a336ea195a62
037cbd92-1434-4dff-be88-5d6bd55c59be
761fcee8-89b0-47d1-b546-b0eeb22b0bf7
72aab5c8-dd09-47cc-8031-9d2d35b6c2e3
9f7ac269-1727-47df-b86b-d07b3ec0bd4a
9b7c6037-ded7-45ec-89ec-77e4f815635e
6b6c56fb-8c97-4983-a1a8-ef7f1046c751
62060a85-d09b-499c-80b8-290adbf9c2cd
cb3c5368-1744-4241-968d-efc66c550a09
49028ca9-315a-49cc-aa50-209b26f39e9d
fad373b5-1cb4-48c3-9aed-50ebc4d63bbc
e4f7a3bf-f13d-4e87-9c3b-affd7765f3a1
4ea1dda3-0089-4be5-9149-0d56c52353cb
28b56a30-562e-4186-a639-f90b8db42868

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)

f6b70c4e-f44c-11f0-872b-4cf95d479851
f6b70cb2-f44c-11f0-872b-4cf95d479851
f6b70d16-f44c-11f0-872b-4cf95d479851
f6b70d7a-f44c-11f0-872b-4cf95d479851
f6b70dde-f44c-11f0-872b-4cf95d479851
f6b70e38-f44c-11f0-872b-4cf95d479851
f6b70e92-f44c-11f0-872b-4cf95d479851
f6b70ef6-f44c-11f0-872b-4cf95d479851
f6b70f50-f44c-11f0-872b-4cf95d479851
f6b70faa-f44c-11f0-872b-4cf95d479851
f6b7100e-f44c-11f0-872b-4cf95d479851
f6b71072-f44c-11f0-872b-4cf95d479851
f6b710d6-f44c-11f0-872b-4cf95d479851
f6b71144-f44c-11f0-872b-4cf95d479851
f6b711a8-f44c-11f0-872b-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)

e6bf3c18-2302-8201-87ea-5ce32bd83b97
4f103e18-2302-8201-87ea-5ce32bd83b97
5af73f18-2302-8201-87ea-5ce32bd83b97
d3544018-2302-8201-87ea-5ce32bd83b97
6ff24118-2302-8201-87ea-5ce32bd83b97
42dd4218-2302-8201-87ea-5ce32bd83b97
8df64318-2302-8201-87ea-5ce32bd83b97
e07b4418-2302-8201-87ea-5ce32bd83b97
aa9b4518-2302-8201-87ea-5ce32bd83b97
133c4618-2302-8201-87ea-5ce32bd83b97
4d7e4718-2302-8201-87ea-5ce32bd83b97
974f4818-2302-8201-87ea-5ce32bd83b97
c24f4918-2302-8201-87ea-5ce32bd83b97
c2a54a18-2302-8201-87ea-5ce32bd83b97
a9244b18-2302-8201-87ea-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: