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)

019a7930-8a86-7a9c-8152-19c2ba77465c
019a7930-8a86-7c4a-9175-fe896eda925a
019a7930-8a86-7d8e-95d6-75cbf04abda5
019a7930-8a86-7eb1-8d95-ca87cba3118d
019a7930-8a86-7fcf-bc03-c50bee219753
019a7930-8a87-70ea-9f88-cbe04c767a1c
019a7930-8a87-7209-aa7f-5452ca6facb5
019a7930-8a87-7323-977e-4b9b1f2a6871
019a7930-8a87-743e-8450-92d4a53c6330
019a7930-8a87-7559-a6d1-4ba31c74a328
019a7930-8a87-7677-a397-fc010dc08aa0
019a7930-8a87-7792-8c10-915d2488088a
019a7930-8a87-78ad-abb4-3e4a336563d0
019a7930-8a87-79cb-a822-93de53af9c21
019a7930-8a87-7ae6-87c3-b8a70c1f7659

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)

1f0bff00-ba49-69be-95c1-4cf95d479851
1f0bff00-ba49-6b58-95c1-4cf95d479851
1f0bff00-ba49-6c3e-95c1-4cf95d479851
1f0bff00-ba49-6d10-95c1-4cf95d479851
1f0bff00-ba49-6dce-95c1-4cf95d479851
1f0bff00-ba49-6e8c-95c1-4cf95d479851
1f0bff00-ba49-6f54-95c1-4cf95d479851
1f0bff00-ba4a-6012-95c1-4cf95d479851
1f0bff00-ba4a-60d0-95c1-4cf95d479851
1f0bff00-ba4a-618e-95c1-4cf95d479851
1f0bff00-ba4a-62ec-95c1-4cf95d479851
1f0bff00-ba4a-63be-95c1-4cf95d479851
1f0bff00-ba4a-647c-95c1-4cf95d479851
1f0bff00-ba4a-6544-95c1-4cf95d479851
1f0bff00-ba4a-6602-95c1-4cf95d479851

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)

ae46f957-d2f7-494a-a305-3d33b17b0af3
c0026c2b-8298-4004-9fb5-f038673abc52
84d3da58-cb14-4f25-967a-003084bd6c9a
87b7a1e3-b712-4eb2-9b36-bd2e306cb007
4c67b96a-43ab-469f-b2c6-b94f5c8e12a3
46776b64-d92e-4b73-9283-6639f3f11ef2
bab8843f-4352-4a90-9e5c-7d30a6ef4af2
83cce1b5-ef0b-4380-aa16-13a8a32a3bc9
025efc5e-9a3e-471a-8617-5c1a108f2f1d
8035cce2-e4fd-422f-9a3b-ab6a173cb055
537541aa-7c3a-4cc0-8eb5-3f7983f70bc8
90764e7c-b43a-4b56-96db-1e5ba454fb62
b0aaca33-6234-45a1-be7d-bb7a766009aa
9f121d59-819f-4648-b3ec-4cbcbba880a4
46ba1b2b-51a9-4c02-9491-3bddc8cfee0d

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)

0ba4ab0c-bff0-11f0-95c1-4cf95d479851
0ba4ab7a-bff0-11f0-95c1-4cf95d479851
0ba4abd4-bff0-11f0-95c1-4cf95d479851
0ba4ac38-bff0-11f0-95c1-4cf95d479851
0ba4ac92-bff0-11f0-95c1-4cf95d479851
0ba4acf6-bff0-11f0-95c1-4cf95d479851
0ba4ad5a-bff0-11f0-95c1-4cf95d479851
0ba4adb4-bff0-11f0-95c1-4cf95d479851
0ba4ae18-bff0-11f0-95c1-4cf95d479851
0ba4ae72-bff0-11f0-95c1-4cf95d479851
0ba4aed6-bff0-11f0-95c1-4cf95d479851
0ba4af30-bff0-11f0-95c1-4cf95d479851
0ba4af94-bff0-11f0-95c1-4cf95d479851
0ba4aff8-bff0-11f0-95c1-4cf95d479851
0ba4b05c-bff0-11f0-95c1-4cf95d479851

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)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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) = WRONG!!!
-  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 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)

4c1eb00f-2f04-8c13-87e9-5ce32bd83b97
dd41b10f-2f04-8c13-87e9-5ce32bd83b97
7946b20f-2f04-8c13-87e9-5ce32bd83b97
4525b30f-2f04-8c13-87e9-5ce32bd83b97
e4d7b40f-2f04-8c13-87e9-5ce32bd83b97
fd11b50f-2f04-8c13-87e9-5ce32bd83b97
9087b60f-2f04-8c13-87e9-5ce32bd83b97
1779b70f-2f04-8c13-87e9-5ce32bd83b97
4a9fb80f-2f04-8c13-87e9-5ce32bd83b97
cabcb90f-2f04-8c13-87e9-5ce32bd83b97
43c2ba0f-2f04-8c13-87e9-5ce32bd83b97
11edbb0f-2f04-8c13-87e9-5ce32bd83b97
d956bc0f-2f04-8c13-87e9-5ce32bd83b97
0c7cbd0f-2f04-8c13-87e9-5ce32bd83b97
7977be0f-2f04-8c13-87e9-5ce32bd83b97

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: