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)

019bb6cb-7035-799a-a9c5-5f1f92decc6f
019bb6cb-7035-7b96-b5ef-afa4a46ca7e4
019bb6cb-7035-7ce2-a165-ebb3805314ed
019bb6cb-7035-7e05-ae11-7fa8759db5cd
019bb6cb-7035-7f1f-bb68-7ccdbb32512b
019bb6cb-7036-703a-90ac-cada2fbb8d2d
019bb6cb-7036-7154-98b0-81400005d757
019bb6cb-7036-726b-8625-a4670394c081
019bb6cb-7036-7386-add0-a62eda2c9062
019bb6cb-7036-749c-ac77-3aaed871b524
019bb6cb-7036-75b7-a4e8-98b22374be11
019bb6cb-7036-76d1-aabe-16c2c1e17a4c
019bb6cb-7036-77e8-a457-34cf4ff4acf2
019bb6cb-7036-7907-885c-55b9164b237a
019bb6cb-7036-7a1d-932b-2246c103a1ac

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)

1f0f0667-e509-6b42-8e59-4cf95d479851
1f0f0667-e509-6cdc-8e59-4cf95d479851
1f0f0667-e509-6dc2-8e59-4cf95d479851
1f0f0667-e509-6e8a-8e59-4cf95d479851
1f0f0667-e509-6f48-8e59-4cf95d479851
1f0f0667-e50a-6010-8e59-4cf95d479851
1f0f0667-e50a-60ce-8e59-4cf95d479851
1f0f0667-e50a-6182-8e59-4cf95d479851
1f0f0667-e50a-6240-8e59-4cf95d479851
1f0f0667-e50a-62fe-8e59-4cf95d479851
1f0f0667-e50a-6434-8e59-4cf95d479851
1f0f0667-e50a-64fc-8e59-4cf95d479851
1f0f0667-e50a-65ba-8e59-4cf95d479851
1f0f0667-e50a-6678-8e59-4cf95d479851
1f0f0667-e50a-6736-8e59-4cf95d479851

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)

1c268ac1-19ae-48b9-a97a-6d6c6a480b57
f57cfad8-e105-4026-9860-05a287b37c5a
1092605c-d378-42cd-9a32-08c3c2a006b9
708c47de-0211-4fdf-8688-f1cdd92aaa4f
ee8f291d-06c3-4599-aa14-50caea2e9be0
81dd9b16-7f75-4daf-ab1a-84cf71756199
400301c3-a432-4f36-8f28-298c14b3858e
119a670c-5e57-451f-912c-95582430f062
03ca006c-edb1-4243-8af8-f5f339a3baf5
96520e85-31b6-47be-b569-251ee81492fe
8e3f502a-7464-4937-b64f-10b823e84281
310fe004-a976-4b07-a743-fa906dc5ef45
c3b87960-1c81-45a0-99a4-bea77dd201e5
cb96d4b6-1642-4469-b02c-6890183c6e97
e5c66c22-e1b4-493c-9bbc-52e4039d0662

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)

7e50ac40-f066-11f0-8e59-4cf95d479851
7e50acae-f066-11f0-8e59-4cf95d479851
7e50ad08-f066-11f0-8e59-4cf95d479851
7e50ad76-f066-11f0-8e59-4cf95d479851
7e50adda-f066-11f0-8e59-4cf95d479851
7e50ae34-f066-11f0-8e59-4cf95d479851
7e50aea2-f066-11f0-8e59-4cf95d479851
7e50af06-f066-11f0-8e59-4cf95d479851
7e50af6a-f066-11f0-8e59-4cf95d479851
7e50afce-f066-11f0-8e59-4cf95d479851
7e50b032-f066-11f0-8e59-4cf95d479851
7e50b08c-f066-11f0-8e59-4cf95d479851
7e50b0f0-f066-11f0-8e59-4cf95d479851
7e50b154-f066-11f0-8e59-4cf95d479851
7e50b1ae-f066-11f0-8e59-4cf95d479851

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)

e1058004-5802-8d00-87ea-5ce32bd83b97
64c98104-5802-8d00-87ea-5ce32bd83b97
bd408204-5802-8d00-87ea-5ce32bd83b97
c2bc8304-5802-8d00-87ea-5ce32bd83b97
a72d8404-5802-8d00-87ea-5ce32bd83b97
2b9f8504-5802-8d00-87ea-5ce32bd83b97
cfa28704-5802-8d00-87ea-5ce32bd83b97
178f8804-5802-8d00-87ea-5ce32bd83b97
b91c8904-5802-8d00-87ea-5ce32bd83b97
703a8a04-5802-8d00-87ea-5ce32bd83b97
18698b04-5802-8d00-87ea-5ce32bd83b97
63b18c04-5802-8d00-87ea-5ce32bd83b97
51528d04-5802-8d00-87ea-5ce32bd83b97
3e628e04-5802-8d00-87ea-5ce32bd83b97
60598f04-5802-8d00-87ea-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: