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)

019b5724-06e5-7e46-ba61-472df6921216
019b5724-06e6-701d-901c-ca353c901037
019b5724-06e6-7169-9454-02153477bdd3
019b5724-06e6-72bd-a632-914da6238ed1
019b5724-06e6-73e0-9741-654d79a2c6f4
019b5724-06e6-74fa-a5c8-3dcd7c7c2ece
019b5724-06e6-7615-a455-36cf6f923ddb
019b5724-06e6-7730-89f9-f5c850b37899
019b5724-06e6-784a-84b0-f0362989f531
019b5724-06e6-7965-925d-3c3e9281197b
019b5724-06e6-7a84-882b-b9f30df63295
019b5724-06e6-7b9e-9acc-ec3c0104b160
019b5724-06e6-7cb9-b8dc-152b3c9d23b5
019b5724-06e6-7daf-9fa7-bcbf9e6e96a2
019b5724-06e6-7ed1-857d-551189ea5a9a

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)

1f0e1ce0-2cee-610a-a56d-4cf95d479851
1f0e1ce0-2cee-62d6-a56d-4cf95d479851
1f0e1ce0-2cee-63bc-a56d-4cf95d479851
1f0e1ce0-2cee-648e-a56d-4cf95d479851
1f0e1ce0-2cee-6556-a56d-4cf95d479851
1f0e1ce0-2cee-661e-a56d-4cf95d479851
1f0e1ce0-2cee-66dc-a56d-4cf95d479851
1f0e1ce0-2cee-679a-a56d-4cf95d479851
1f0e1ce0-2cee-6862-a56d-4cf95d479851
1f0e1ce0-2cee-6920-a56d-4cf95d479851
1f0e1ce0-2cee-6a6a-a56d-4cf95d479851
1f0e1ce0-2cee-6b3c-a56d-4cf95d479851
1f0e1ce0-2cee-6bfa-a56d-4cf95d479851
1f0e1ce0-2cee-6cb8-a56d-4cf95d479851
1f0e1ce0-2cee-6d80-a56d-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)

7ee9692d-5545-4f41-9cbd-a26769e955d2
76b3b948-4e43-41ff-9c5d-1bf0f8b8b90c
f9e66672-7dc4-4b68-83ae-705c54a28eb9
ab6c8e34-6aa4-4c86-90a0-5ae79a2ab4c2
a015fee2-0b25-4a5e-aa1d-33f1ce48c099
8a83a520-7c5d-4052-b034-17cd28bd2645
7ae1010a-a11e-4d52-8db0-4f4d472eb1af
6acc1fb8-86a7-46cb-9152-04d8c4b5dfce
deef55d5-1604-4649-b690-0a865d14f36c
8e225240-5501-4f7e-9ec0-d9e15b94a8a1
eb1a602c-32e5-49c5-9682-b68076c76cd5
9fa6a66f-395d-4f2c-960e-54a146e50d72
53c7546e-3102-4cd5-8354-bb468f2eb8cb
3d31d30e-f655-4af7-befa-62b9ed2ab91d
de67c7a8-ca98-4927-87c3-ec1e8b3d5c11

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)

02cef29e-e1ce-11f0-a56d-4cf95d479851
02cef302-e1ce-11f0-a56d-4cf95d479851
02cef370-e1ce-11f0-a56d-4cf95d479851
02cef3d4-e1ce-11f0-a56d-4cf95d479851
02cef42e-e1ce-11f0-a56d-4cf95d479851
02cef488-e1ce-11f0-a56d-4cf95d479851
02cef4ec-e1ce-11f0-a56d-4cf95d479851
02cef546-e1ce-11f0-a56d-4cf95d479851
02cef5a0-e1ce-11f0-a56d-4cf95d479851
02cef60e-e1ce-11f0-a56d-4cf95d479851
02cef672-e1ce-11f0-a56d-4cf95d479851
02cef6d6-e1ce-11f0-a56d-4cf95d479851
02cef73a-e1ce-11f0-a56d-4cf95d479851
02cef79e-e1ce-11f0-a56d-4cf95d479851
02cef802-e1ce-11f0-a56d-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)

a0d88211-bd04-8716-87e9-5ce32bd83b97
a66c8311-bd04-8716-87e9-5ce32bd83b97
bfc38411-bd04-8716-87e9-5ce32bd83b97
65d08511-bd04-8716-87e9-5ce32bd83b97
c3fe8711-bd04-8716-87e9-5ce32bd83b97
69cd8811-bd04-8716-87e9-5ce32bd83b97
3ae88911-bd04-8716-87e9-5ce32bd83b97
47eb8a11-bd04-8716-87e9-5ce32bd83b97
dc9d8b11-bd04-8716-87e9-5ce32bd83b97
e6ed8c11-bd04-8716-87e9-5ce32bd83b97
83068d11-bd04-8716-87e9-5ce32bd83b97
15b68e11-bd04-8716-87e9-5ce32bd83b97
c8ac8f11-bd04-8716-87e9-5ce32bd83b97
40129011-bd04-8716-87e9-5ce32bd83b97
51429111-bd04-8716-87e9-5ce32bd83b97

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

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: