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)

019bee09-4d20-75aa-991a-729cb7374ff0
019bee09-4d20-774c-9512-70cc4ab69509
019bee09-4d20-7894-ba9e-3d75379922cf
019bee09-4d20-79af-823f-b2dcc682d6b0
019bee09-4d20-7acd-b96b-0210f7fa8f7a
019bee09-4d20-7be4-88f0-a348f215ddc0
019bee09-4d20-7cfe-abcd-8f8000a371ad
019bee09-4d20-7e15-8eb0-5c0ae90164cc
019bee09-4d20-7f2c-923a-fbda276f8c1a
019bee09-4d21-7042-96e9-5880120f732d
019bee09-4d21-7171-8155-7602034c50ec
019bee09-4d21-72cd-b792-4a9de6bcbc51
019bee09-4d21-7421-8248-bc572a72f0a1
019bee09-4d21-7575-ac62-a36b7469e424
019bee09-4d21-76c5-862a-9f86125aabdd

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)

1f0f8d45-ed62-6e64-932f-4cf95d479851
1f0f8d45-ed63-6116-932f-4cf95d479851
1f0f8d45-ed63-6224-932f-4cf95d479851
1f0f8d45-ed63-62ec-932f-4cf95d479851
1f0f8d45-ed63-63be-932f-4cf95d479851
1f0f8d45-ed63-6486-932f-4cf95d479851
1f0f8d45-ed63-654e-932f-4cf95d479851
1f0f8d45-ed63-66ca-932f-4cf95d479851
1f0f8d45-ed63-6846-932f-4cf95d479851
1f0f8d45-ed63-69c2-932f-4cf95d479851
1f0f8d45-ed63-6bd4-932f-4cf95d479851
1f0f8d45-ed63-6d50-932f-4cf95d479851
1f0f8d45-ed63-6ec2-932f-4cf95d479851
1f0f8d45-ed64-6034-932f-4cf95d479851
1f0f8d45-ed64-61a6-932f-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)

ed1da5f9-b78e-4b20-9451-60294eeca173
2074b773-6e92-4cf1-b26b-55c7eeb396e9
c0921538-e930-438a-905b-6def2ab8a0e9
2ae5ef51-cccd-4b53-b812-f8766f02ea09
3f28afe0-8a65-4879-9273-6abb83ad90e8
874e8f1b-63c0-497a-b648-8fe6826fb01f
340d31af-9018-449f-9343-217a9422d51a
e9242c44-7e5f-4fdf-90ff-560db740f6ed
9008f29d-a51e-4265-97ea-3a53cd0fc930
c8b89748-25cd-4b9e-8240-78302d9b4b9e
ee100b62-d3ac-44b6-86ae-551e4475a20e
587aaa7b-1a66-4f03-b485-5a6d46df93af
41de5a6a-b70c-4ff1-8001-102672ee2e41
c646d5fe-582d-48ab-93f6-00513b801434
beb4c583-2bb3-46d0-94ee-7e3373f5c3c7

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)

5ed64a20-f8d4-11f0-932f-4cf95d479851
5ed64b1a-f8d4-11f0-932f-4cf95d479851
5ed64bd8-f8d4-11f0-932f-4cf95d479851
5ed64c82-f8d4-11f0-932f-4cf95d479851
5ed64d54-f8d4-11f0-932f-4cf95d479851
5ed64e12-f8d4-11f0-932f-4cf95d479851
5ed64eb2-f8d4-11f0-932f-4cf95d479851
5ed64f34-f8d4-11f0-932f-4cf95d479851
5ed64f98-f8d4-11f0-932f-4cf95d479851
5ed65006-f8d4-11f0-932f-4cf95d479851
5ed65074-f8d4-11f0-932f-4cf95d479851
5ed650e2-f8d4-11f0-932f-4cf95d479851
5ed65150-f8d4-11f0-932f-4cf95d479851
5ed651b4-f8d4-11f0-932f-4cf95d479851
5ed65218-f8d4-11f0-932f-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)

1897a22d-ce00-8801-87ea-5ce32bd83b97
6728a32d-ce00-8801-87ea-5ce32bd83b97
aa48a42d-ce00-8801-87ea-5ce32bd83b97
136ca52d-ce00-8801-87ea-5ce32bd83b97
427ca62d-ce00-8801-87ea-5ce32bd83b97
65bfa72d-ce00-8801-87ea-5ce32bd83b97
6027a82d-ce00-8801-87ea-5ce32bd83b97
4b73a92d-ce00-8801-87ea-5ce32bd83b97
967aaa2d-ce00-8801-87ea-5ce32bd83b97
ddafab2d-ce00-8801-87ea-5ce32bd83b97
17fdac2d-ce00-8801-87ea-5ce32bd83b97
f9d6ad2d-ce00-8801-87ea-5ce32bd83b97
87d5ae2d-ce00-8801-87ea-5ce32bd83b97
36ffaf2d-ce00-8801-87ea-5ce32bd83b97
376cb02d-ce00-8801-87ea-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

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: