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)

01a13f2a-7272-7ec9-8828-cd6fefdc7909
01a13f2a-7273-70c1-8baf-2bc48ff91f41
01a13f2a-7273-7252-ab1e-cc4781163fa7
01a13f2a-7273-73a6-94cb-8ad2576aeec2
01a13f2a-7273-74fe-a9fd-24e5e7bdf7f7
01a13f2a-7273-7646-9b19-191c7b8e5b4b
01a13f2a-7273-7761-8902-b6631be17cf5
01a13f2a-7273-7888-a939-f8147e56b311
01a13f2a-7273-799e-b0b9-30d423f9c51b
01a13f2a-7273-7ab1-83a9-bca7d29779dc
01a13f2a-7273-7bc7-b310-010c27a49952
01a13f2a-7273-7cda-9df8-8e9857594491
01a13f2a-7273-7df0-9468-282384d2cb35
01a13f2a-7273-7f07-80ef-f1488d5810f2
01a13f2a-7274-701d-8510-3eb6b8c7756d

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)

1f1c8857-d981-67c8-b8cd-4cf95d479851
1f1c8857-d981-69d0-b8cd-4cf95d479851
1f1c8857-d981-6ac0-b8cd-4cf95d479851
1f1c8857-d981-6b92-b8cd-4cf95d479851
1f1c8857-d981-6c64-b8cd-4cf95d479851
1f1c8857-d981-6d22-b8cd-4cf95d479851
1f1c8857-d981-6dea-b8cd-4cf95d479851
1f1c8857-d981-6ea8-b8cd-4cf95d479851
1f1c8857-d981-6f70-b8cd-4cf95d479851
1f1c8857-d982-602e-b8cd-4cf95d479851
1f1c8857-d982-6182-b8cd-4cf95d479851
1f1c8857-d982-6254-b8cd-4cf95d479851
1f1c8857-d982-631c-b8cd-4cf95d479851
1f1c8857-d982-63da-b8cd-4cf95d479851
1f1c8857-d982-6498-b8cd-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)

7d98257e-c885-11f1-b8cd-4cf95d479851
7d9825e2-c885-11f1-b8cd-4cf95d479851
7d982646-c885-11f1-b8cd-4cf95d479851
7d9826b4-c885-11f1-b8cd-4cf95d479851
7d982718-c885-11f1-b8cd-4cf95d479851
7d98277c-c885-11f1-b8cd-4cf95d479851
7d9827e0-c885-11f1-b8cd-4cf95d479851
7d982844-c885-11f1-b8cd-4cf95d479851
7d9828a8-c885-11f1-b8cd-4cf95d479851
7d98290c-c885-11f1-b8cd-4cf95d479851
7d982970-c885-11f1-b8cd-4cf95d479851
7d9829d4-c885-11f1-b8cd-4cf95d479851
7d982a38-c885-11f1-b8cd-4cf95d479851
7d982a9c-c885-11f1-b8cd-4cf95d479851
7d982b00-c885-11f1-b8cd-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)

b6f9d908-8602-8012-87ea-5ce32bd83b97
53f4da08-8602-8012-87ea-5ce32bd83b97
af05dc08-8602-8012-87ea-5ce32bd83b97
9417dd08-8602-8012-87ea-5ce32bd83b97
0813de08-8602-8012-87ea-5ce32bd83b97
6f68df08-8602-8012-87ea-5ce32bd83b97
f841e008-8602-8012-87ea-5ce32bd83b97
6008e108-8602-8012-87ea-5ce32bd83b97
ef47e208-8602-8012-87ea-5ce32bd83b97
2803e308-8602-8012-87ea-5ce32bd83b97
5caee408-8602-8012-87ea-5ce32bd83b97
ece0e508-8602-8012-87ea-5ce32bd83b97
d227e608-8602-8012-87ea-5ce32bd83b97
465ee708-8602-8012-87ea-5ce32bd83b97
5d6de808-8602-8012-87ea-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)

24289de3-21ba-4066-94aa-13fc2e896158
8e269ee6-dfe7-4015-b021-a441fcd17c53
c04feac1-f861-481b-bc9c-cdc2fc610bd8
72661eaf-effd-42bd-8c9a-56d955881560
308707fa-07ef-4e0b-8414-110fcd2f882e
ef501ec7-1453-4ce0-b655-fbe8de402053
9e78884d-f3a3-4218-a5d7-6474fd326f99
94cd990e-15e0-4fc2-b114-66f669f7d3ad
2e99c04e-b4cc-4ece-8910-8c07525e537c
6a4f6624-34d6-4cef-9c19-ddffd90eb463
93339baf-cc69-4eb8-98a6-517ffe9d2ef7
f9e27467-5946-48e4-8f09-190e29cedf8e
6b5ccd85-dd8b-44b6-a201-8774e57cac38
c104fd0b-9e66-4932-b78e-c13189e08627
080c6fdb-82cf-4bdf-87e6-393ef65b46ce

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: