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)

018f7535-1454-7619-ac55-ea35d505e57a
018f7535-1454-7903-82f0-bf6bdbd0a43a
018f7535-1454-7a67-972a-f9bde5d67f8b
018f7535-1454-7b92-8142-37db60531513
018f7535-1454-7cb5-8cca-b5c1677783ca
018f7535-1454-7e1d-adda-46b8a9bb55f9
018f7535-1454-7f7d-bd13-fbaeccffafec
018f7535-1455-7179-843b-8ac0945630fa
018f7535-1455-72c5-b3bc-cfb771bf71b3
018f7535-1455-73fc-ba89-d575fce2ae49
018f7535-1455-751f-88aa-270e0ea646ff
018f7535-1455-7646-a0a7-ffdd4b564b03
018f7535-1455-7765-a6e4-3ee833fe1260
018f7535-1455-7884-ad15-aadaa33f2301
018f7535-1455-79a2-abdd-013f590ab6dc

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)

1ef11a47-ceb9-6466-a02a-4cf95d479851
1ef11a47-ceb9-6650-a02a-4cf95d479851
1ef11a47-ceb9-6740-a02a-4cf95d479851
1ef11a47-ceb9-6812-a02a-4cf95d479851
1ef11a47-ceb9-68da-a02a-4cf95d479851
1ef11a47-ceb9-69a2-a02a-4cf95d479851
1ef11a47-ceb9-6a6a-a02a-4cf95d479851
1ef11a47-ceb9-6b28-a02a-4cf95d479851
1ef11a47-ceb9-6be6-a02a-4cf95d479851
1ef11a47-ceb9-6ca4-a02a-4cf95d479851
1ef11a47-ceb9-6e20-a02a-4cf95d479851
1ef11a47-ceb9-6ee8-a02a-4cf95d479851
1ef11a47-ceb9-6fb0-a02a-4cf95d479851
1ef11a47-ceba-606e-a02a-4cf95d479851
1ef11a47-ceba-612c-a02a-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)

c7088504-ecf9-41ab-8d6b-40eeb2abca23
d4fb2311-0d6a-4a20-b989-795172327bb6
79ae90f7-af19-464c-90f1-64eff5681b6c
d4820cc0-ec4c-45e8-ab43-b1c4639cb420
dba8db43-f86c-49f4-aab1-9f68105dcf05
5f680b1c-5bef-4a96-85b4-dc1c106dc4ea
431e6531-b447-4403-ac89-bfc3e3ff9a51
3769b404-e390-4fb0-a897-8844406087e9
811e7f12-ea34-488c-938a-e5ba10e1aa34
9b97b571-fe79-4a44-b230-712b196d78bc
2d635ef9-ca57-4c9e-92be-e50abeee36c0
99293b37-f430-41fa-ba13-7e991d884bd4
c00f8c0c-7a88-433a-9496-6342390da98c
234b0058-e71c-46c7-b214-f775edbd521c
63bee489-99d0-4f9c-8ed6-7ccabcaa51ac

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)

7ceba690-11a4-11ef-a02a-4cf95d479851
7ceba6f4-11a4-11ef-a02a-4cf95d479851
7ceba758-11a4-11ef-a02a-4cf95d479851
7ceba7c6-11a4-11ef-a02a-4cf95d479851
7ceba82a-11a4-11ef-a02a-4cf95d479851
7ceba88e-11a4-11ef-a02a-4cf95d479851
7ceba8f2-11a4-11ef-a02a-4cf95d479851
7ceba956-11a4-11ef-a02a-4cf95d479851
7ceba9b0-11a4-11ef-a02a-4cf95d479851
7cebaa1e-11a4-11ef-a02a-4cf95d479851
7cebaa82-11a4-11ef-a02a-4cf95d479851
7cebaae6-11a4-11ef-a02a-4cf95d479851
7cebab54-11a4-11ef-a02a-4cf95d479851
7cebabb8-11a4-11ef-a02a-4cf95d479851
7cebac1c-11a4-11ef-a02a-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)

3f0cfd03-00e3-8087-87e8-5ce32bd83b96
0ac2fe03-00e3-8087-87e8-5ce32bd83b96
8076ff03-00e3-8087-87e8-5ce32bd83b96
177c0104-00e3-8087-87e8-5ce32bd83b96
02c00204-00e3-8087-87e8-5ce32bd83b96
f9a60304-00e3-8087-87e8-5ce32bd83b96
eeea0404-00e3-8087-87e8-5ce32bd83b96
08c70504-00e3-8087-87e8-5ce32bd83b96
17e30604-00e3-8087-87e8-5ce32bd83b96
71e40704-00e3-8087-87e8-5ce32bd83b96
48260804-00e3-8087-87e8-5ce32bd83b96
d3070904-00e3-8087-87e8-5ce32bd83b96
0f990a04-00e3-8087-87e8-5ce32bd83b96
d2500b04-00e3-8087-87e8-5ce32bd83b96
50040c04-00e3-8087-87e8-5ce32bd83b96

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: