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)

019b99bf-124e-7a73-9148-ea0cba61d242
019b99bf-124e-7c2e-b2a8-fed4ce80eda8
019b99bf-124e-7d71-8298-bdccf4238d48
019b99bf-124e-7e98-97e4-d1fdeee9d703
019b99bf-124e-7fb3-b4cd-87c99ccbaff4
019b99bf-124f-70cd-935f-bb56c8932f89
019b99bf-124f-71e8-bf3a-84212e421235
019b99bf-124f-7303-88e5-7c70eb4aa9a1
019b99bf-124f-741d-b220-d4545026c88b
019b99bf-124f-7538-939c-f14ccc06950d
019b99bf-124f-7657-9f14-b40b81674e72
019b99bf-124f-7771-83b5-7e0e7504fdb6
019b99bf-124f-788c-be7e-38cf64db42e3
019b99bf-124f-79a2-af62-08898f135d27
019b99bf-124f-7abd-921d-0f19f3e2e893

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)

1f0ebf7c-b3c8-6e02-a6f1-4cf95d479851
1f0ebf7c-b3c8-6fce-a6f1-4cf95d479851
1f0ebf7c-b3c9-60c8-a6f1-4cf95d479851
1f0ebf7c-b3c9-61a4-a6f1-4cf95d479851
1f0ebf7c-b3c9-6280-a6f1-4cf95d479851
1f0ebf7c-b3c9-6352-a6f1-4cf95d479851
1f0ebf7c-b3c9-642e-a6f1-4cf95d479851
1f0ebf7c-b3c9-650a-a6f1-4cf95d479851
1f0ebf7c-b3c9-65dc-a6f1-4cf95d479851
1f0ebf7c-b3c9-66b8-a6f1-4cf95d479851
1f0ebf7c-b3c9-6834-a6f1-4cf95d479851
1f0ebf7c-b3c9-691a-a6f1-4cf95d479851
1f0ebf7c-b3c9-69e2-a6f1-4cf95d479851
1f0ebf7c-b3c9-6ab4-a6f1-4cf95d479851
1f0ebf7c-b3c9-6b7c-a6f1-4cf95d479851

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)

ef641a36-253e-49be-8a8a-8f68bb22a909
cffbe94b-d383-4362-9aa5-0c5bc4b04fc0
ea2a4501-9096-451e-8f8e-d2a73a424baa
ea1739e2-07f9-471c-b9d4-a91a94d1def9
328a69c1-970a-4605-bb9a-9daf70c2937c
aae44aba-7cd7-47d4-8dc0-139bd092a680
e4486624-ac3f-434f-b477-9c139e3d9e1a
c68048f5-da18-4498-a08e-8b63f379f687
e97fe456-83ca-4cce-bab6-27aaa3ecaf5f
476f8336-7c09-4129-9880-966be0d923c3
5eb82150-3363-4789-bc61-2360a6ee16b4
4eb7ca74-70a9-4e2f-b18e-cc0a57047cc0
1a260c72-a25b-480c-a52e-5dfa40c666ba
d8ea7116-1049-40c6-96a6-c5c197865d9e
b9350174-9073-4c6e-925c-fdb6355ba262

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)

cb3ca0a4-ebf7-11f0-a6f1-4cf95d479851
cb3ca112-ebf7-11f0-a6f1-4cf95d479851
cb3ca176-ebf7-11f0-a6f1-4cf95d479851
cb3ca1da-ebf7-11f0-a6f1-4cf95d479851
cb3ca23e-ebf7-11f0-a6f1-4cf95d479851
cb3ca298-ebf7-11f0-a6f1-4cf95d479851
cb3ca2f2-ebf7-11f0-a6f1-4cf95d479851
cb3ca356-ebf7-11f0-a6f1-4cf95d479851
cb3ca3ba-ebf7-11f0-a6f1-4cf95d479851
cb3ca414-ebf7-11f0-a6f1-4cf95d479851
cb3ca478-ebf7-11f0-a6f1-4cf95d479851
cb3ca4dc-ebf7-11f0-a6f1-4cf95d479851
cb3ca540-ebf7-11f0-a6f1-4cf95d479851
cb3ca5ae-ebf7-11f0-a6f1-4cf95d479851
cb3ca61c-ebf7-11f0-a6f1-4cf95d479851

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)

1486c422-5d04-8700-87ea-5ce32bd83b97
2929c522-5d04-8700-87ea-5ce32bd83b97
9164c622-5d04-8700-87ea-5ce32bd83b97
0a5ec722-5d04-8700-87ea-5ce32bd83b97
cb9fc822-5d04-8700-87ea-5ce32bd83b97
54ffc922-5d04-8700-87ea-5ce32bd83b97
a0b9ca22-5d04-8700-87ea-5ce32bd83b97
eb51cb22-5d04-8700-87ea-5ce32bd83b97
f7afcc22-5d04-8700-87ea-5ce32bd83b97
31c2cd22-5d04-8700-87ea-5ce32bd83b97
61c6cf22-5d04-8700-87ea-5ce32bd83b97
e8c5d022-5d04-8700-87ea-5ce32bd83b97
f57fd122-5d04-8700-87ea-5ce32bd83b97
6949d222-5d04-8700-87ea-5ce32bd83b97
09c7d322-5d04-8700-87ea-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: