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)

019a5df1-228f-7e8c-9f83-ed705382f9bc
019a5df1-2290-708c-a1b4-4a599dc1144c
019a5df1-2290-71f8-a415-262e92c0de66
019a5df1-2290-733c-b224-01324fe041a2
019a5df1-2290-747b-8d6e-963a2a92e75e
019a5df1-2290-75b7-9926-a1d3201351c9
019a5df1-2290-76f2-9812-93af9410f41f
019a5df1-2290-782e-a467-461c4318552a
019a5df1-2290-7969-b746-f946deb3903d
019a5df1-2290-7aa4-9767-772879feece6
019a5df1-2290-7be0-94d7-fdb4b3267c15
019a5df1-2290-7d1b-aa12-d2e031a779d3
019a5df1-2290-7e57-9daf-01d9b0915a62
019a5df1-2290-7f92-8898-85679e392d25
019a5df1-2291-70cd-8343-607356ede6f8

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)

1f0bbc7a-ed78-6830-b340-4cf95d479851
1f0bbc7a-ed78-6a56-b340-4cf95d479851
1f0bbc7a-ed78-6baa-b340-4cf95d479851
1f0bbc7a-ed78-6cd6-b340-4cf95d479851
1f0bbc7a-ed78-6e0c-b340-4cf95d479851
1f0bbc7a-ed78-6f2e-b340-4cf95d479851
1f0bbc7a-ed79-605a-b340-4cf95d479851
1f0bbc7a-ed79-617c-b340-4cf95d479851
1f0bbc7a-ed79-629e-b340-4cf95d479851
1f0bbc7a-ed79-63c0-b340-4cf95d479851
1f0bbc7a-ed79-65aa-b340-4cf95d479851
1f0bbc7a-ed79-66e0-b340-4cf95d479851
1f0bbc7a-ed79-6802-b340-4cf95d479851
1f0bbc7a-ed79-692e-b340-4cf95d479851
1f0bbc7a-ed79-6a50-b340-4cf95d479851

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)

a2393566-a09e-4204-b5d5-40531c1228d5
7db90553-ca34-4524-8b82-7e713bd49586
d22af488-c549-48ff-945a-a18d61f309cd
5b451bf0-4269-42d5-8b7f-af67cd330134
726845ad-3969-4fc5-9746-41ea9212e26d
b596c422-41b0-4c7b-942f-55c4cc5746ae
e343f004-6408-4fca-bf9e-70f6a6f8199d
a17f2782-9f3a-43cf-aa44-a672f790e00b
cda2698f-8d75-4645-afa2-a11103994f89
cc85837a-ad6b-4950-864a-a5ed867cba79
cab9081c-6065-4ea0-a2ab-e0ce85b27c4e
f50084d7-2799-4252-bb19-ec7037574b8b
8b44616d-391a-4d0f-be4a-20e0af1f42ab
f543d8f9-1574-416c-ae5f-f64d0d2715d5
c9de2f6e-3684-4263-8533-fcd09c83774d

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)

aed7a0e0-bbc7-11f0-b340-4cf95d479851
aed7a16c-bbc7-11f0-b340-4cf95d479851
aed7a1ee-bbc7-11f0-b340-4cf95d479851
aed7a27a-bbc7-11f0-b340-4cf95d479851
aed7a306-bbc7-11f0-b340-4cf95d479851
aed7a388-bbc7-11f0-b340-4cf95d479851
aed7a414-bbc7-11f0-b340-4cf95d479851
aed7a4a0-bbc7-11f0-b340-4cf95d479851
aed7a52c-bbc7-11f0-b340-4cf95d479851
aed7a5ae-bbc7-11f0-b340-4cf95d479851
aed7a63a-bbc7-11f0-b340-4cf95d479851
aed7a6c6-bbc7-11f0-b340-4cf95d479851
aed7a752-bbc7-11f0-b340-4cf95d479851
aed7a7d4-bbc7-11f0-b340-4cf95d479851
aed7a860-bbc7-11f0-b340-4cf95d479851

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)

25e6790f-8c02-8713-87e9-5ce32bd83b97
15fa7a0f-8c02-8713-87e9-5ce32bd83b97
07d97b0f-8c02-8713-87e9-5ce32bd83b97
dd837c0f-8c02-8713-87e9-5ce32bd83b97
c4467d0f-8c02-8713-87e9-5ce32bd83b97
af117e0f-8c02-8713-87e9-5ce32bd83b97
4c627f0f-8c02-8713-87e9-5ce32bd83b97
98c8800f-8c02-8713-87e9-5ce32bd83b97
2f11810f-8c02-8713-87e9-5ce32bd83b97
b565820f-8c02-8713-87e9-5ce32bd83b97
fcfb830f-8c02-8713-87e9-5ce32bd83b97
28db840f-8c02-8713-87e9-5ce32bd83b97
3edc850f-8c02-8713-87e9-5ce32bd83b97
57fd870f-8c02-8713-87e9-5ce32bd83b97
1c22880f-8c02-8713-87e9-5ce32bd83b97

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: