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)

01a1e01d-faec-7d8e-9cdf-24443a5c85ec
01a1e01d-faec-7f34-9cdf-68883785c932
01a1e01d-faed-7073-b27c-c5f25090ae12
01a1e01d-faed-718e-a3ed-29a93f84d261
01a1e01d-faed-72a4-9a15-96a5876b5c05
01a1e01d-faed-73cf-a4c8-7a5e0cb2d555
01a1e01d-faed-74e6-8565-a6479e851485
01a1e01d-faed-75f8-991e-e2ef8c685d06
01a1e01d-faed-770b-aab3-93c962a896fd
01a1e01d-faed-781d-ac1b-c3e30cec7fed
01a1e01d-faed-7930-80c8-58f556d5e466
01a1e01d-faed-7a42-80c9-fad267222eb3
01a1e01d-faed-7b54-9ae6-9c5ede2a66f3
01a1e01d-faed-7c67-9ecd-b3c78b25d67f
01a1e01d-faed-7d7d-b300-e848af40172a

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)

1f1e114a-69b2-6eb0-a94a-4cf95d479851
1f1e114a-69b3-6072-a94a-4cf95d479851
1f1e114a-69b3-6162-a94a-4cf95d479851
1f1e114a-69b3-6234-a94a-4cf95d479851
1f1e114a-69b3-6306-a94a-4cf95d479851
1f1e114a-69b3-63ce-a94a-4cf95d479851
1f1e114a-69b3-6496-a94a-4cf95d479851
1f1e114a-69b3-655e-a94a-4cf95d479851
1f1e114a-69b3-6626-a94a-4cf95d479851
1f1e114a-69b3-66ee-a94a-4cf95d479851
1f1e114a-69b3-684c-a94a-4cf95d479851
1f1e114a-69b3-6928-a94a-4cf95d479851
1f1e114a-69b3-69f0-a94a-4cf95d479851
1f1e114a-69b3-6ac2-a94a-4cf95d479851
1f1e114a-69b3-6b8a-a94a-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)

a69b3c66-e114-11f1-a94a-4cf95d479851
a69b3cd4-e114-11f1-a94a-4cf95d479851
a69b3d2e-e114-11f1-a94a-4cf95d479851
a69b3d92-e114-11f1-a94a-4cf95d479851
a69b3e32-e114-11f1-a94a-4cf95d479851
a69b3e96-e114-11f1-a94a-4cf95d479851
a69b3ef0-e114-11f1-a94a-4cf95d479851
a69b3f54-e114-11f1-a94a-4cf95d479851
a69b3fae-e114-11f1-a94a-4cf95d479851
a69b4008-e114-11f1-a94a-4cf95d479851
a69b406c-e114-11f1-a94a-4cf95d479851
a69b40c6-e114-11f1-a94a-4cf95d479851
a69b4120-e114-11f1-a94a-4cf95d479851
a69b4184-e114-11f1-a94a-4cf95d479851
a69b41de-e114-11f1-a94a-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)

42f29917-f303-8f13-87ea-5ce32bd83b97
90fb9a17-f303-8f13-87ea-5ce32bd83b97
b5729b17-f303-8f13-87ea-5ce32bd83b97
a6c39c17-f303-8f13-87ea-5ce32bd83b97
363b9d17-f303-8f13-87ea-5ce32bd83b97
c5179e17-f303-8f13-87ea-5ce32bd83b97
08d49f17-f303-8f13-87ea-5ce32bd83b97
0fc5a017-f303-8f13-87ea-5ce32bd83b97
76f0a117-f303-8f13-87ea-5ce32bd83b97
870aa217-f303-8f13-87ea-5ce32bd83b97
8dfea317-f303-8f13-87ea-5ce32bd83b97
a3b8a417-f303-8f13-87ea-5ce32bd83b97
c8c5a517-f303-8f13-87ea-5ce32bd83b97
2feba617-f303-8f13-87ea-5ce32bd83b97
fdf3a717-f303-8f13-87ea-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)

e9539fcc-45c6-4df8-b8d1-0f70d32919c9
f02e110f-cb74-4a63-b985-72c8038a419a
bc6a042a-c180-454f-981d-cf08f741d4c9
53f51a8f-a5b7-4385-846f-01758f938606
c1fe8420-6ff8-4509-a13a-b8988d4df819
121fb89d-b204-4590-8ae6-59da641bcc73
0c92be11-cb36-4992-a5b7-d600bc4a3ef7
9412acfe-cba7-42d6-8084-3875a7a880d9
d1b4c84d-aaf7-4e8c-9621-69efa8a7dce4
f8b7739a-8780-442e-b1f0-7737d5c4512f
353c202b-5762-4dea-b510-8881a3aa2bb9
67e65921-1759-4b70-b958-265633bd87a8
f788ca2d-0156-4e58-b1d6-52fac6599fa1
672d2b7a-423e-4448-a14d-0396adc414ca
ae89e4a3-c537-40c0-8b94-889630d17cdb

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: