UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f7bc7-8554-709c-8bca-6744c128199e
019f7bc7-8554-7290-b4c2-a3d00a6899bf
019f7bc7-8554-73d3-a481-13f8f18f6fd0
019f7bc7-8554-74ee-b15b-f71e9108e28a
019f7bc7-8554-7605-a0cc-bb2061937482
019f7bc7-8554-7717-9273-b8a4d57d817f
019f7bc7-8554-7829-9f49-d00baccc00f2
019f7bc7-8554-793c-8089-a7570bc2fdaa
019f7bc7-8554-7a4a-8f72-7052927b65dd
019f7bc7-8554-7b5d-9371-d4b7d871ea82
019f7bc7-8554-7c6f-916f-a9e7ba7b97d4
019f7bc7-8554-7d82-bbcf-914496a8df59
019f7bc7-8554-7e90-ad28-9c22a9ee38f4
019f7bc7-8554-7fa2-a7d5-165b4739b350
019f7bc7-8555-70b9-82ab-1b11fc288d28

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)

1f183a53-5498-6e72-ba2c-4cf95d479851
1f183a53-5499-607a-ba2c-4cf95d479851
1f183a53-5499-616a-ba2c-4cf95d479851
1f183a53-5499-6246-ba2c-4cf95d479851
1f183a53-5499-630e-ba2c-4cf95d479851
1f183a53-5499-63d6-ba2c-4cf95d479851
1f183a53-5499-64a8-ba2c-4cf95d479851
1f183a53-5499-6566-ba2c-4cf95d479851
1f183a53-5499-662e-ba2c-4cf95d479851
1f183a53-5499-6700-ba2c-4cf95d479851
1f183a53-5499-6854-ba2c-4cf95d479851
1f183a53-5499-6930-ba2c-4cf95d479851
1f183a53-5499-69f8-ba2c-4cf95d479851
1f183a53-5499-6ac0-ba2c-4cf95d479851
1f183a53-5499-6b88-ba2c-4cf95d479851

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)

35499c6e-83a5-11f1-ba2c-4cf95d479851
35499cdc-83a5-11f1-ba2c-4cf95d479851
35499d4a-83a5-11f1-ba2c-4cf95d479851
35499db8-83a5-11f1-ba2c-4cf95d479851
35499e1c-83a5-11f1-ba2c-4cf95d479851
35499e8a-83a5-11f1-ba2c-4cf95d479851
35499eee-83a5-11f1-ba2c-4cf95d479851
35499f52-83a5-11f1-ba2c-4cf95d479851
35499fc0-83a5-11f1-ba2c-4cf95d479851
3549a024-83a5-11f1-ba2c-4cf95d479851
3549a092-83a5-11f1-ba2c-4cf95d479851
3549a100-83a5-11f1-ba2c-4cf95d479851
3549a164-83a5-11f1-ba2c-4cf95d479851
3549a1d2-83a5-11f1-ba2c-4cf95d479851
3549a22c-83a5-11f1-ba2c-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

53e53415-7d04-880c-87ea-5ce32bd83b97
cf2f3515-7d04-880c-87ea-5ce32bd83b97
92d13615-7d04-880c-87ea-5ce32bd83b97
27303815-7d04-880c-87ea-5ce32bd83b97
86bc3915-7d04-880c-87ea-5ce32bd83b97
eb9e3a15-7d04-880c-87ea-5ce32bd83b97
83ca3b15-7d04-880c-87ea-5ce32bd83b97
279b3c15-7d04-880c-87ea-5ce32bd83b97
b73d3d15-7d04-880c-87ea-5ce32bd83b97
b2393e15-7d04-880c-87ea-5ce32bd83b97
75973f15-7d04-880c-87ea-5ce32bd83b97
8d534015-7d04-880c-87ea-5ce32bd83b97
e51c4115-7d04-880c-87ea-5ce32bd83b97
67894215-7d04-880c-87ea-5ce32bd83b97
d0d94315-7d04-880c-87ea-5ce32bd83b97

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)

9e3ac88d-5955-4c2a-9834-e51012afb0a2
c1da46cd-c705-40c4-8cc5-1508adddb8ce
10452003-f7fd-41b4-afda-e5623e63d9f6
cf0a9112-ab75-435c-affe-ef33809683f1
df8d6a7f-a113-4f93-be47-5576a1c570e2
83e79c75-15fe-44f1-b4a7-48f85d9c518c
6c9b5a52-2039-4b77-8831-89369ff1fb2d
948ff42e-a405-4418-b5fa-22be3e3d1639
2816a239-8089-44f1-9983-4039b15a3c4d
82cf4906-21ef-491d-9518-b1d66a5aad4c
3c66a44f-3381-4752-84e6-0dc1bfd4a489
b35a7c70-c466-4913-a479-2b1125c42bbb
b621dca2-a26a-4c4c-abee-ce6fe1bff665
a9c63b66-6b5e-4345-840e-3b8df3f278e2
0a7a66f6-9192-44bf-b13d-67314fbbbecc

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: