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)

019ea502-5a59-716d-a04f-e319df2931e0
019ea502-5a59-7338-bb3b-c4bf1c31a20a
019ea502-5a59-7473-90a1-8e14e750c4ee
019ea502-5a59-758e-9a8b-2dbac3acee1b
019ea502-5a59-76a4-be99-e49a59331370
019ea502-5a59-77bb-84fe-3dea7b714487
019ea502-5a59-78d1-aa60-7c1725dfe694
019ea502-5a59-79e4-ae56-627d30fc69ea
019ea502-5a59-7b03-afce-cedb6ba76fdc
019ea502-5a59-7c19-bd08-fc1a5342d21c
019ea502-5a59-7d30-8fe1-44a6d78d0f5e
019ea502-5a59-7e46-85ee-f5f0024183f0
019ea502-5a59-7f5d-a89f-fef773542ea1
019ea502-5a5a-7073-aac8-0f07e054ab74
019ea502-5a5a-718a-b020-0ba26fe1d960

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)

1f162dfb-f6aa-63c0-9d1a-4cf95d479851
1f162dfb-f6aa-65be-9d1a-4cf95d479851
1f162dfb-f6aa-66b8-9d1a-4cf95d479851
1f162dfb-f6aa-6794-9d1a-4cf95d479851
1f162dfb-f6aa-6866-9d1a-4cf95d479851
1f162dfb-f6aa-6938-9d1a-4cf95d479851
1f162dfb-f6aa-69f6-9d1a-4cf95d479851
1f162dfb-f6aa-6abe-9d1a-4cf95d479851
1f162dfb-f6aa-6b86-9d1a-4cf95d479851
1f162dfb-f6aa-6c44-9d1a-4cf95d479851
1f162dfb-f6aa-6dd4-9d1a-4cf95d479851
1f162dfb-f6aa-6fb4-9d1a-4cf95d479851
1f162dfb-f6ab-60ae-9d1a-4cf95d479851
1f162dfb-f6ab-6176-9d1a-4cf95d479851
1f162dfb-f6ab-6234-9d1a-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)

bf6ab31a-62df-11f1-9d1a-4cf95d479851
bf6ab37e-62df-11f1-9d1a-4cf95d479851
bf6ab3e2-62df-11f1-9d1a-4cf95d479851
bf6ab446-62df-11f1-9d1a-4cf95d479851
bf6ab4a0-62df-11f1-9d1a-4cf95d479851
bf6ab504-62df-11f1-9d1a-4cf95d479851
bf6ab572-62df-11f1-9d1a-4cf95d479851
bf6ab5cc-62df-11f1-9d1a-4cf95d479851
bf6ab630-62df-11f1-9d1a-4cf95d479851
bf6ab68a-62df-11f1-9d1a-4cf95d479851
bf6ab6ee-62df-11f1-9d1a-4cf95d479851
bf6ab748-62df-11f1-9d1a-4cf95d479851
bf6ab7ac-62df-11f1-9d1a-4cf95d479851
bf6ab806-62df-11f1-9d1a-4cf95d479851
bf6ab860-62df-11f1-9d1a-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)

e38c630f-8700-8f09-87ea-5ce32bd83b97
1f35640f-8700-8f09-87ea-5ce32bd83b97
485c650f-8700-8f09-87ea-5ce32bd83b97
7b76660f-8700-8f09-87ea-5ce32bd83b97
1ed0670f-8700-8f09-87ea-5ce32bd83b97
1191680f-8700-8f09-87ea-5ce32bd83b97
413c690f-8700-8f09-87ea-5ce32bd83b97
e30e6a0f-8700-8f09-87ea-5ce32bd83b97
f4086b0f-8700-8f09-87ea-5ce32bd83b97
02116c0f-8700-8f09-87ea-5ce32bd83b97
008a6d0f-8700-8f09-87ea-5ce32bd83b97
f2ce6e0f-8700-8f09-87ea-5ce32bd83b97
5aa26f0f-8700-8f09-87ea-5ce32bd83b97
648c700f-8700-8f09-87ea-5ce32bd83b97
5633710f-8700-8f09-87ea-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)

a5643f58-97fe-4e2c-99ba-9136f1d37d6d
0ddddd0d-22c2-4f19-8881-fae8e12478f8
4d9df483-a268-4cc3-83c2-96f84f182509
59a44aa4-bf3b-4fa7-b329-615f681ddae9
01a9a91a-ee50-47c4-bc9b-b2b1b7ece468
419b238b-77f3-46be-86b0-60c626389818
80e8a8be-804f-4dee-8752-3279b623f223
1637af37-a881-45a3-9af4-5c94747b98bf
3703fb67-687d-4663-9138-8dd0f0aaab36
808dab93-e6cc-4370-b252-a91db374cace
f1851d31-ff7d-4229-9fef-c51cb2a464be
6a306595-c92b-439a-b210-267d36aa85fe
639abfe5-ce0a-43ae-9a55-307bacc9fc77
4fe09947-4836-4968-b53c-c1540f4b36bf
f0759de0-80e4-4ec6-abe2-e3e87cfb6e63

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: