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)

01971884-e627-75e4-9a11-3db16c26c1e8
01971884-e627-77a6-bca0-90d013abda5f
01971884-e627-78ee-8bf9-f52c98b4326e
01971884-e627-7a32-844a-0a9373dc05ce
01971884-e627-7b5d-b22b-fa693b10d452
01971884-e627-7c84-b671-32fdf70d76ea
01971884-e627-7da2-a457-49ede85825b1
01971884-e627-7ec9-9bba-d5e296ef218d
01971884-e627-7ff0-93f1-6a423320fd80
01971884-e628-7113-a8ca-8905a9badfe0
01971884-e628-7232-99aa-965b6854609a
01971884-e628-7354-abfd-148b886ff25e
01971884-e628-747b-a394-d146ea0d96bc
01971884-e628-759e-a9a3-017d20670f70
01971884-e628-76c1-b845-67607a5e9362

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)

1f03bffd-adfd-602e-a2c5-4cf95d479851
1f03bffd-adfd-61dc-a2c5-4cf95d479851
1f03bffd-adfd-62cc-a2c5-4cf95d479851
1f03bffd-adfd-639e-a2c5-4cf95d479851
1f03bffd-adfd-6466-a2c5-4cf95d479851
1f03bffd-adfd-652e-a2c5-4cf95d479851
1f03bffd-adfd-65f6-a2c5-4cf95d479851
1f03bffd-adfd-66c8-a2c5-4cf95d479851
1f03bffd-adfd-6786-a2c5-4cf95d479851
1f03bffd-adfd-684e-a2c5-4cf95d479851
1f03bffd-adfd-6998-a2c5-4cf95d479851
1f03bffd-adfd-6a6a-a2c5-4cf95d479851
1f03bffd-adfd-6b32-a2c5-4cf95d479851
1f03bffd-adfd-6bfa-a2c5-4cf95d479851
1f03bffd-adfd-6cc2-a2c5-4cf95d479851

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)

baf7885f-adba-42db-b836-4502e2e1b4b8
9ffc61ae-f90c-4efc-8b9d-b6ea5c11ff6d
60732d2b-5c3e-432e-824c-99246d107f2e
10be9272-1a3d-455c-80f1-d180bb9f55eb
4107be16-95d5-4d98-8fe3-9f3cb68f1fda
46c93350-80d9-44d4-8079-95575c9173eb
c3c5822c-4cf2-4057-a7a2-4c5e371ebb01
44c0941d-ec0a-4063-995b-3500f1a5471a
0648b29c-0468-4326-bb58-9b9a4e15de98
8b71c0a9-8a23-45d5-8523-3a8c2c889f00
bca79450-6c3d-41c9-b989-471facc3ecde
93a173e1-d630-4fd5-a00c-3a19ef062b53
e65725b8-6b61-4824-883c-775225977dbe
32b70586-5b03-4977-8691-b50610287c5e
dc8dedc4-fb0f-46ce-b827-12110b87e5da

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)

dadfe1f4-3bff-11f0-a2c5-4cf95d479851
dadfe262-3bff-11f0-a2c5-4cf95d479851
dadfe2c6-3bff-11f0-a2c5-4cf95d479851
dadfe32a-3bff-11f0-a2c5-4cf95d479851
dadfe3f2-3bff-11f0-a2c5-4cf95d479851
dadfe460-3bff-11f0-a2c5-4cf95d479851
dadfe4c4-3bff-11f0-a2c5-4cf95d479851
dadfe532-3bff-11f0-a2c5-4cf95d479851
dadfe596-3bff-11f0-a2c5-4cf95d479851
dadfe604-3bff-11f0-a2c5-4cf95d479851
dadfe668-3bff-11f0-a2c5-4cf95d479851
dadfe6cc-3bff-11f0-a2c5-4cf95d479851
dadfe730-3bff-11f0-a2c5-4cf95d479851
dadfe79e-3bff-11f0-a2c5-4cf95d479851
dadfe816-3bff-11f0-a2c5-4cf95d479851

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)

40885434-04bb-8094-87e9-5ce32bd83b96
f1285534-04bb-8094-87e9-5ce32bd83b96
63d85634-04bb-8094-87e9-5ce32bd83b96
f9ef5734-04bb-8094-87e9-5ce32bd83b96
e7e05834-04bb-8094-87e9-5ce32bd83b96
fff75934-04bb-8094-87e9-5ce32bd83b96
c8605a34-04bb-8094-87e9-5ce32bd83b96
a3895b34-04bb-8094-87e9-5ce32bd83b96
c4015c34-04bb-8094-87e9-5ce32bd83b96
94d25d34-04bb-8094-87e9-5ce32bd83b96
9da25e34-04bb-8094-87e9-5ce32bd83b96
ae045f34-04bb-8094-87e9-5ce32bd83b96
57e96034-04bb-8094-87e9-5ce32bd83b96
a6666234-04bb-8094-87e9-5ce32bd83b96
4a7e6334-04bb-8094-87e9-5ce32bd83b96

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: