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)

01928762-de98-728c-bcaa-bdf4ef086404
01928762-de98-742e-a3ca-0431a094d7e6
01928762-de98-7575-8866-a630a9a63695
01928762-de98-769c-a1a6-a14f59c9d568
01928762-de98-77bb-ae73-dffecfb46b8b
01928762-de98-78da-88f7-3057d9d254df
01928762-de98-79f8-b5a0-fe2664e63bba
01928762-de98-7b17-8892-12f13437d3f7
01928762-de98-7c36-bbc9-be30a8f1270e
01928762-de98-7d50-9e8d-511600b316bb
01928762-de98-7e6f-870b-20e76111c644
01928762-de98-7f8e-9458-2fb77526ec11
01928762-de99-70ad-a67b-36fd058928d8
01928762-de99-71cb-a651-c242d88b9e42
01928762-de99-72ee-967b-9c209c2398b8

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)

1ef899a9-9988-64e8-89a0-4cf95d479851
1ef899a9-9988-6678-89a0-4cf95d479851
1ef899a9-9988-6768-89a0-4cf95d479851
1ef899a9-9988-684e-89a0-4cf95d479851
1ef899a9-9988-6920-89a0-4cf95d479851
1ef899a9-9988-69e8-89a0-4cf95d479851
1ef899a9-9988-6aba-89a0-4cf95d479851
1ef899a9-9988-6b78-89a0-4cf95d479851
1ef899a9-9988-6c40-89a0-4cf95d479851
1ef899a9-9988-6d08-89a0-4cf95d479851
1ef899a9-9988-6e48-89a0-4cf95d479851
1ef899a9-9988-6f1a-89a0-4cf95d479851
1ef899a9-9988-6fec-89a0-4cf95d479851
1ef899a9-9989-60b4-89a0-4cf95d479851
1ef899a9-9989-6186-89a0-4cf95d479851

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)

147a564c-e8fd-4c45-b393-ef4c7ef753a6
0f93e19c-97dd-4c62-94bf-f16d3c531562
08c540bb-0cba-4a47-b282-f0437da33655
cad12e82-f33f-4974-ad6d-9c5dda6e57e6
ba268c52-e394-40dc-b327-cbd7ef0bb2a1
5a3e9361-893d-4aa6-b490-e9a28afdcc1b
d4a98bc4-58bf-4c65-912f-9bfeb56856ee
a5d36559-72fe-4b9e-bd09-72c58f67e962
3020e3cf-34b5-4888-aa6e-f76abede53a0
62e5dbe6-1a39-438a-ae24-cc9935512285
7a6e7f34-91d2-4857-8617-fc28d0eaa9a6
afe4a2bb-36a9-45d7-820a-829b4a0d19a9
0f31974f-9451-4a43-9980-73cda5e57263
e308a547-e73c-42b4-8cfc-e92aef2f1ceb
d1bc2899-d6ec-409f-8467-23c8772c33a3

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)

999896b8-899a-11ef-89a0-4cf95d479851
99989726-899a-11ef-89a0-4cf95d479851
99989780-899a-11ef-89a0-4cf95d479851
999897e4-899a-11ef-89a0-4cf95d479851
9998983e-899a-11ef-89a0-4cf95d479851
999898a2-899a-11ef-89a0-4cf95d479851
99989906-899a-11ef-89a0-4cf95d479851
99989960-899a-11ef-89a0-4cf95d479851
999899c4-899a-11ef-89a0-4cf95d479851
99989a1e-899a-11ef-89a0-4cf95d479851
99989a78-899a-11ef-89a0-4cf95d479851
99989adc-899a-11ef-89a0-4cf95d479851
99989b2c-899a-11ef-89a0-4cf95d479851
99989b90-899a-11ef-89a0-4cf95d479851
99989be0-899a-11ef-89a0-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

d412aa24-049a-811f-87e8-5ce32bd83b96
e1a3ab24-049a-811f-87e8-5ce32bd83b96
78ceac24-049a-811f-87e8-5ce32bd83b96
4103ad24-049a-811f-87e8-5ce32bd83b96
1f78ae24-049a-811f-87e8-5ce32bd83b96
5980af24-049a-811f-87e8-5ce32bd83b96
a1f8b024-049a-811f-87e8-5ce32bd83b96
3e97b124-049a-811f-87e8-5ce32bd83b96
593fb224-049a-811f-87e8-5ce32bd83b96
58a3b324-049a-811f-87e8-5ce32bd83b96
57a8b424-049a-811f-87e8-5ce32bd83b96
88a0b524-049a-811f-87e8-5ce32bd83b96
a8b5b624-049a-811f-87e8-5ce32bd83b96
afe1b724-049a-811f-87e8-5ce32bd83b96
bd31b824-049a-811f-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: