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)

019cc90c-c810-7e19-bf9f-a8ee3b34c392
019cc90c-c810-7ffc-8e11-479254d80be6
019cc90c-c811-7175-8bbe-bc5d821a3260
019cc90c-c811-72ad-a784-35baf1f05911
019cc90c-c811-7411-af15-ea1f98d60951
019cc90c-c811-7550-8d49-b9094dd563eb
019cc90c-c811-7673-8d41-4dfeb658b8af
019cc90c-c811-77b3-89e9-a79927774d5d
019cc90c-c811-7907-b483-5284270315cb
019cc90c-c811-7a46-9ebc-d3eec36e8725
019cc90c-c811-7b96-bb2c-7a0a9637edd0
019cc90c-c811-7cea-b558-323c5aee120b
019cc90c-c811-7e32-9956-90fc36f47a39
019cc90c-c811-7f7d-8aeb-ad8bb9668547
019cc90c-c812-70de-8108-8f48597ad098

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)

1f11a3f9-6c88-656a-9f9c-4cf95d479851
1f11a3f9-6c88-670e-9f9c-4cf95d479851
1f11a3f9-6c88-67f4-9f9c-4cf95d479851
1f11a3f9-6c88-6920-9f9c-4cf95d479851
1f11a3f9-6c88-6aa6-9f9c-4cf95d479851
1f11a3f9-6c88-6c2c-9f9c-4cf95d479851
1f11a3f9-6c88-6db2-9f9c-4cf95d479851
1f11a3f9-6c88-6f06-9f9c-4cf95d479851
1f11a3f9-6c88-6fec-9f9c-4cf95d479851
1f11a3f9-6c89-60aa-9f9c-4cf95d479851
1f11a3f9-6c89-61f4-9f9c-4cf95d479851
1f11a3f9-6c89-62c6-9f9c-4cf95d479851
1f11a3f9-6c89-6384-9f9c-4cf95d479851
1f11a3f9-6c89-64d8-9f9c-4cf95d479851
1f11a3f9-6c89-6654-9f9c-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)

7b06cdba-0ab7-4475-a768-5573550683bd
59640b8a-059b-49bc-8622-81d4037202e2
f1871316-5c7b-4a1e-88a9-219ceedc9fdf
ac93cd68-a960-479f-b200-8171cd2dad59
db48b920-00f7-4c1f-ae24-81e2d62bc0a7
803d13ed-1dab-4dac-9bcd-11f98a593a61
b5fac29b-f66d-4b91-9f76-01d1d6e84ab7
ece4d788-af50-41eb-b008-5031d869e4f0
04964591-aa70-43b6-a27e-21ddb61d8575
e27af377-c7e3-4839-8f9f-db9e7f76528c
9e4f4b85-5adf-49b8-97d7-49af7aa0eb32
c7316bd6-6bba-4c0e-b078-e93e5550741f
1ec9f63c-e3ca-49ba-a0cf-ebf04f2f9e96
633601cd-6712-465e-9727-96b0daa4ff66
d13e37e2-dacb-40c0-b057-e34e4dcd3f34

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)

96c89ce4-1a3f-11f1-9f9c-4cf95d479851
96c89d52-1a3f-11f1-9f9c-4cf95d479851
96c89dac-1a3f-11f1-9f9c-4cf95d479851
96c89e10-1a3f-11f1-9f9c-4cf95d479851
96c89e74-1a3f-11f1-9f9c-4cf95d479851
96c89eec-1a3f-11f1-9f9c-4cf95d479851
96c89f78-1a3f-11f1-9f9c-4cf95d479851
96c8a018-1a3f-11f1-9f9c-4cf95d479851
96c8a0b8-1a3f-11f1-9f9c-4cf95d479851
96c8a14e-1a3f-11f1-9f9c-4cf95d479851
96c8a1ee-1a3f-11f1-9f9c-4cf95d479851
96c8a298-1a3f-11f1-9f9c-4cf95d479851
96c8a324-1a3f-11f1-9f9c-4cf95d479851
96c8a3ba-1a3f-11f1-9f9c-4cf95d479851
96c8a464-1a3f-11f1-9f9c-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)

bfcf0518-c703-8204-87ea-5ce32bd83b97
29a50618-c703-8204-87ea-5ce32bd83b97
5c900718-c703-8204-87ea-5ce32bd83b97
35c00818-c703-8204-87ea-5ce32bd83b97
6e9b0918-c703-8204-87ea-5ce32bd83b97
e7da0a18-c703-8204-87ea-5ce32bd83b97
80820b18-c703-8204-87ea-5ce32bd83b97
e0d20c18-c703-8204-87ea-5ce32bd83b97
db750d18-c703-8204-87ea-5ce32bd83b97
2a600e18-c703-8204-87ea-5ce32bd83b97
603c0f18-c703-8204-87ea-5ce32bd83b97
dbe31018-c703-8204-87ea-5ce32bd83b97
4f001118-c703-8204-87ea-5ce32bd83b97
f7451218-c703-8204-87ea-5ce32bd83b97
34d41318-c703-8204-87ea-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: