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)

019badd8-8c51-7442-a9ac-21c9e05e9fd9
019badd8-8c51-7694-8360-530f0d3964cd
019badd8-8c51-77d8-8918-3e9b63b18c84
019badd8-8c51-78fe-9093-dbbd8c82d9e7
019badd8-8c51-7a19-bbed-093dd36f5e06
019badd8-8c51-7b38-bbc1-354da7aadf55
019badd8-8c51-7c57-8761-5abb8ba323aa
019badd8-8c51-7d71-b29f-e915944bd2d1
019badd8-8c51-7e8c-828d-7c53fd5832e3
019badd8-8c51-7fa6-80ee-fbb8eb6e56d7
019badd8-8c52-70c1-86fa-3fd211ae928a
019badd8-8c52-71e0-a367-e4919f87b86e
019badd8-8c52-72fe-91e0-588995e36499
019badd8-8c52-7419-9fe9-f09ffc64cc21
019badd8-8c52-7534-9b94-f5d2614aad27

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)

1f0ef08e-e6a9-6586-b29b-4cf95d479851
1f0ef08e-e6a9-6734-b29b-4cf95d479851
1f0ef08e-e6a9-6824-b29b-4cf95d479851
1f0ef08e-e6a9-6900-b29b-4cf95d479851
1f0ef08e-e6a9-69c8-b29b-4cf95d479851
1f0ef08e-e6a9-6a90-b29b-4cf95d479851
1f0ef08e-e6a9-6b62-b29b-4cf95d479851
1f0ef08e-e6a9-6c2a-b29b-4cf95d479851
1f0ef08e-e6a9-6cf2-b29b-4cf95d479851
1f0ef08e-e6a9-6dba-b29b-4cf95d479851
1f0ef08e-e6a9-6efa-b29b-4cf95d479851
1f0ef08e-e6aa-6012-b29b-4cf95d479851
1f0ef08e-e6aa-618e-b29b-4cf95d479851
1f0ef08e-e6aa-62ec-b29b-4cf95d479851
1f0ef08e-e6aa-63d2-b29b-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)

854503f7-f468-4c52-b2c4-f0caba27b0a7
905367a7-d86b-429c-9b66-0aa7e55bc427
22dfbfd7-8125-4c39-8725-fd36126c140a
8e1719b4-856f-4fe0-9a34-c0aab8c58c4a
bd072fb6-6adc-418c-bf3e-b3f074f46dd5
7398088d-3a2c-462c-8eac-6088d98841f0
22377839-271e-4c72-a770-d9bb17384f97
e4d76426-609c-4bbc-8c62-f13c0ffb8f76
a28c0cd6-5e8a-4770-b09d-6a2269d914b6
33a17cf6-b99d-4914-b7a5-059a94d4050f
46edb784-c8a2-4d58-9557-cf0fc30b33c2
f706db3d-6c18-4734-b50d-f5e3f3ff4ffc
83c67c17-3a91-4fc6-a211-dec505ab0fe8
f177bea7-0df9-42fd-bfb0-a4060841160a
805048ae-4099-4f3d-8096-96f913802fc7

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)

ee6aa904-ef08-11f0-b29b-4cf95d479851
ee6aa968-ef08-11f0-b29b-4cf95d479851
ee6aa9cc-ef08-11f0-b29b-4cf95d479851
ee6aaa30-ef08-11f0-b29b-4cf95d479851
ee6aaa94-ef08-11f0-b29b-4cf95d479851
ee6aaaee-ef08-11f0-b29b-4cf95d479851
ee6aab52-ef08-11f0-b29b-4cf95d479851
ee6aabc0-ef08-11f0-b29b-4cf95d479851
ee6aac24-ef08-11f0-b29b-4cf95d479851
ee6aac88-ef08-11f0-b29b-4cf95d479851
ee6aacf6-ef08-11f0-b29b-4cf95d479851
ee6aad64-ef08-11f0-b29b-4cf95d479851
ee6aadd2-ef08-11f0-b29b-4cf95d479851
ee6aae36-ef08-11f0-b29b-4cf95d479851
ee6aae9a-ef08-11f0-b29b-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)

1b7fb930-d103-8b00-87ea-5ce32bd83b97
7666ba30-d103-8b00-87ea-5ce32bd83b97
9e06bb30-d103-8b00-87ea-5ce32bd83b97
1e51bc30-d103-8b00-87ea-5ce32bd83b97
5cd1bd30-d103-8b00-87ea-5ce32bd83b97
1b09be30-d103-8b00-87ea-5ce32bd83b97
919abf30-d103-8b00-87ea-5ce32bd83b97
6d31c030-d103-8b00-87ea-5ce32bd83b97
d221c130-d103-8b00-87ea-5ce32bd83b97
00f7c230-d103-8b00-87ea-5ce32bd83b97
8a52c330-d103-8b00-87ea-5ce32bd83b97
9233c430-d103-8b00-87ea-5ce32bd83b97
647bc530-d103-8b00-87ea-5ce32bd83b97
a841c630-d103-8b00-87ea-5ce32bd83b97
13afc730-d103-8b00-87ea-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: