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)

01a0fc5f-cf44-75cf-9ab0-ebc5bda8d94c
01a0fc5f-cf44-7779-a6fc-f258c876295d
01a0fc5f-cf44-78b9-9b18-3b217c0233c4
01a0fc5f-cf44-79d3-aa28-2aabfe1abbdc
01a0fc5f-cf44-7aee-b9ca-171ff2f7cd49
01a0fc5f-cf44-7c00-8662-588967b2e697
01a0fc5f-cf44-7d17-9440-e535ce4805b4
01a0fc5f-cf44-7e29-a63d-334e3a42de25
01a0fc5f-cf44-7f4c-b9a8-9b7fc33044d0
01a0fc5f-cf45-7063-ab80-121a899dcb30
01a0fc5f-cf45-7179-9597-f7ce0f8c85b1
01a0fc5f-cf45-7290-b99f-f676a5b2c344
01a0fc5f-cf45-73cb-88fc-0e8f6c6d5cc2
01a0fc5f-cf45-74ea-b3cd-b566ff46c3bb
01a0fc5f-cf45-7600-94a8-8d2cfe08b6f2

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)

1f1be547-211c-6a10-803e-4cf95d479851
1f1be547-211c-6bbe-803e-4cf95d479851
1f1be547-211c-6c9a-803e-4cf95d479851
1f1be547-211c-6d6c-803e-4cf95d479851
1f1be547-211c-6e2a-803e-4cf95d479851
1f1be547-211c-6ee8-803e-4cf95d479851
1f1be547-211c-6f9c-803e-4cf95d479851
1f1be547-211d-6064-803e-4cf95d479851
1f1be547-211d-6118-803e-4cf95d479851
1f1be547-211d-61d6-803e-4cf95d479851
1f1be547-211d-6316-803e-4cf95d479851
1f1be547-211d-63de-803e-4cf95d479851
1f1be547-211d-649c-803e-4cf95d479851
1f1be547-211d-655a-803e-4cf95d479851
1f1be547-211d-660e-803e-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)

7211d6e0-be54-11f1-803e-4cf95d479851
7211d744-be54-11f1-803e-4cf95d479851
7211d79e-be54-11f1-803e-4cf95d479851
7211d802-be54-11f1-803e-4cf95d479851
7211d85c-be54-11f1-803e-4cf95d479851
7211d8b6-be54-11f1-803e-4cf95d479851
7211d91a-be54-11f1-803e-4cf95d479851
7211d974-be54-11f1-803e-4cf95d479851
7211d9ce-be54-11f1-803e-4cf95d479851
7211da32-be54-11f1-803e-4cf95d479851
7211da8c-be54-11f1-803e-4cf95d479851
7211dae6-be54-11f1-803e-4cf95d479851
7211db4a-be54-11f1-803e-4cf95d479851
7211dba4-be54-11f1-803e-4cf95d479851
7211dbfe-be54-11f1-803e-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)

680e8c34-b102-8311-87ea-5ce32bd83b97
cbef8d34-b102-8311-87ea-5ce32bd83b97
65f78e34-b102-8311-87ea-5ce32bd83b97
c1e28f34-b102-8311-87ea-5ce32bd83b97
fb809034-b102-8311-87ea-5ce32bd83b97
857c9134-b102-8311-87ea-5ce32bd83b97
b1009334-b102-8311-87ea-5ce32bd83b97
4cfe9434-b102-8311-87ea-5ce32bd83b97
022c9534-b102-8311-87ea-5ce32bd83b97
49a19634-b102-8311-87ea-5ce32bd83b97
c9a59734-b102-8311-87ea-5ce32bd83b97
14469834-b102-8311-87ea-5ce32bd83b97
4bcf9934-b102-8311-87ea-5ce32bd83b97
efb39a34-b102-8311-87ea-5ce32bd83b97
98219b34-b102-8311-87ea-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)

c8e87fe8-82e7-45f8-8a03-37805092f82d
9f8acacb-cff3-4136-9fc1-fd1034b710b3
9b301024-6a27-4c59-8730-a5e12ddc9fee
27134a4f-bce9-426a-aef8-c4256a78f32d
552068b4-d91c-4362-935f-41d53327444d
d9cf1df6-ba35-4702-8a66-6ee9a71893e1
1416e91d-04d5-4713-a60b-72526bc85b38
e97c8f3e-6959-4c57-b944-33cb6e981986
170f25e0-6998-45fe-bade-3cd21e40bc27
07ae4b4c-748f-45b2-9124-ba179de4f3e9
27e3b467-2238-407d-8e3e-908cdd712b0f
5e6ef841-a2be-4e1a-81ef-a9389d16e3aa
98de5867-225e-4f9a-96c4-391d74b57953
aa8e548b-af86-47ca-924b-e4479bed2c0b
1c8f6611-4072-4a34-98ed-f049828cc2e0

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: