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)

019cb659-547c-7907-8245-7b212b2586ff
019cb659-547c-7a9c-ac2b-454de0476100
019cb659-547c-7be0-8435-5cde5f930e1a
019cb659-547c-7d03-a26a-549a76c65763
019cb659-547c-7e1d-a3e5-7ed58aa7c23d
019cb659-547c-7f3c-9879-7773ead86f44
019cb659-547d-7057-a6f2-8e2eec7cebf2
019cb659-547d-7171-bfd6-ca3f1432ac35
019cb659-547d-728c-82e4-ffa204043a85
019cb659-547d-73a6-9eb4-c5c2557ad1b9
019cb659-547d-74c1-81a5-e4196dcc3975
019cb659-547d-75f8-94f4-f8d99c429c34
019cb659-547d-7740-96b6-8d9477e6d741
019cb659-547d-7898-8bf1-56ea92f9ddde
019cb659-547d-79ec-9d83-c45d245d4023

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)

1f117651-4f5a-6f9a-9825-4cf95d479851
1f117651-4f5b-6206-9825-4cf95d479851
1f117651-4f5b-63b4-9825-4cf95d479851
1f117651-4f5b-6526-9825-4cf95d479851
1f117651-4f5b-667a-9825-4cf95d479851
1f117651-4f5b-67d8-9825-4cf95d479851
1f117651-4f5b-6936-9825-4cf95d479851
1f117651-4f5b-6a94-9825-4cf95d479851
1f117651-4f5b-6bca-9825-4cf95d479851
1f117651-4f5b-6d1e-9825-4cf95d479851
1f117651-4f5b-6f08-9825-4cf95d479851
1f117651-4f5c-6066-9825-4cf95d479851
1f117651-4f5c-61b0-9825-4cf95d479851
1f117651-4f5c-6304-9825-4cf95d479851
1f117651-4f5c-6462-9825-4cf95d479851

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)

47c6e4d9-4a17-4fd7-b8cc-9301d25f02bb
2572d1f1-d7f0-4789-89ea-66ebb13f1ace
a3d58e69-274d-468c-aaeb-7c29468cf273
0c208872-f669-4f22-b197-f0b606c3d6b6
adc13161-5c57-4e36-a106-59480cdefd0a
c0bce340-34e4-4bdc-9aa8-e8e4523446d6
2a19b4e0-8b2c-41c8-91ce-fb896744879d
8a51cf1c-e5aa-4812-a581-fce5da5b836c
5eef55c6-8188-44c8-a73a-e5602bd7f9aa
66809df9-ea98-4994-8db3-9cb9eb53d301
4d254f6f-5e78-4ab3-87e2-e0e673f821db
6a5c213c-61ec-476a-9c80-ccb01387494d
e4f68a08-30f1-4068-a40e-a08c26d40396
d4f75031-c8ae-485f-98f0-eacf42a04476
ea687f65-4959-41af-9eab-cf158d915c6f

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)

14f5cc14-1765-11f1-9825-4cf95d479851
14f5ccbe-1765-11f1-9825-4cf95d479851
14f5cd68-1765-11f1-9825-4cf95d479851
14f5ce08-1765-11f1-9825-4cf95d479851
14f5ceb2-1765-11f1-9825-4cf95d479851
14f5cf52-1765-11f1-9825-4cf95d479851
14f5cffc-1765-11f1-9825-4cf95d479851
14f5d092-1765-11f1-9825-4cf95d479851
14f5d13c-1765-11f1-9825-4cf95d479851
14f5d1dc-1765-11f1-9825-4cf95d479851
14f5d268-1765-11f1-9825-4cf95d479851
14f5d312-1765-11f1-9825-4cf95d479851
14f5d3b2-1765-11f1-9825-4cf95d479851
14f5d452-1765-11f1-9825-4cf95d479851
14f5d4f2-1765-11f1-9825-4cf95d479851

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)

f44b990d-3a00-8f03-87ea-5ce32bd83b97
22939a0d-3a00-8f03-87ea-5ce32bd83b97
4e1f9b0d-3a00-8f03-87ea-5ce32bd83b97
01759c0d-3a00-8f03-87ea-5ce32bd83b97
89449d0d-3a00-8f03-87ea-5ce32bd83b97
97fb9e0d-3a00-8f03-87ea-5ce32bd83b97
86919f0d-3a00-8f03-87ea-5ce32bd83b97
568da00d-3a00-8f03-87ea-5ce32bd83b97
7a5da10d-3a00-8f03-87ea-5ce32bd83b97
61cca20d-3a00-8f03-87ea-5ce32bd83b97
ee5aa30d-3a00-8f03-87ea-5ce32bd83b97
9b7ba40d-3a00-8f03-87ea-5ce32bd83b97
3996a50d-3a00-8f03-87ea-5ce32bd83b97
e77da60d-3a00-8f03-87ea-5ce32bd83b97
f2d1a70d-3a00-8f03-87ea-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: