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)

019ba576-41dd-7f92-af40-b26657168f8a
019ba576-41de-7134-93fd-b76d2dc04a75
019ba576-41de-7273-9abd-0e70b3dc6c5b
019ba576-41de-7396-b3c6-85fe89082abc
019ba576-41de-74b1-a395-c4ef2ec372ac
019ba576-41de-75cb-bfc0-fb2de867f9a9
019ba576-41de-76e2-b7dc-7c5aa6f2fe66
019ba576-41de-77fc-8480-9440830c2a5b
019ba576-41de-7917-98bf-83b02bf174d0
019ba576-41de-7a15-be27-1b33dc61c64d
019ba576-41de-7b30-b562-ad1009da50e1
019ba576-41de-7c4a-8503-2dc26ebf5d37
019ba576-41de-7d65-9eb0-b56af9006f45
019ba576-41de-7e7b-a721-c5b4b115de70
019ba576-41de-7f96-abaf-57adc3377e42

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)

1f0edc16-eee5-69de-8f07-4cf95d479851
1f0edc16-eee5-6b6e-8f07-4cf95d479851
1f0edc16-eee5-6c54-8f07-4cf95d479851
1f0edc16-eee5-6d1c-8f07-4cf95d479851
1f0edc16-eee5-6de4-8f07-4cf95d479851
1f0edc16-eee5-6ea2-8f07-4cf95d479851
1f0edc16-eee5-6f6a-8f07-4cf95d479851
1f0edc16-eee6-6032-8f07-4cf95d479851
1f0edc16-eee6-60f0-8f07-4cf95d479851
1f0edc16-eee6-61a4-8f07-4cf95d479851
1f0edc16-eee6-62ee-8f07-4cf95d479851
1f0edc16-eee6-63b6-8f07-4cf95d479851
1f0edc16-eee6-6474-8f07-4cf95d479851
1f0edc16-eee6-6532-8f07-4cf95d479851
1f0edc16-eee6-65f0-8f07-4cf95d479851

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)

04c5abee-fc42-4277-9089-8d74e0420b2c
d7c4f9e5-7a91-4060-83f8-6073a2cb4e90
47460c51-3664-44bc-b9cc-c440ad40ebc4
133963b8-e8cd-4a2d-83f6-3eda5b8d9bca
8477d3d6-ce18-4efd-a7fe-bddd69002470
0047ac59-2228-45c5-9f59-56e925d9dad2
8903c806-cfe0-4260-9e4b-93ca9c0e03b1
794e6df8-4a2a-4edc-b9b2-ff473697d194
fee76846-2c3a-44b5-8383-ffe47dd7771b
d1c0ba91-41c8-4772-97b0-8d029fd58777
d096ff73-3d39-4f17-bc7e-2165a51d35fb
429cefaf-6c27-47da-bb8e-15b8e4b32811
8c427d82-5bb0-4064-92d2-4a88ad005750
b0bc9da8-7053-4ffa-a91e-82f9e7258dc0
8ccf8526-3392-4681-a797-03b82ff5bdbe

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)

6eee6b0e-edc1-11f0-8f07-4cf95d479851
6eee6b72-edc1-11f0-8f07-4cf95d479851
6eee6bd6-edc1-11f0-8f07-4cf95d479851
6eee6c3a-edc1-11f0-8f07-4cf95d479851
6eee6c9e-edc1-11f0-8f07-4cf95d479851
6eee6d0c-edc1-11f0-8f07-4cf95d479851
6eee6d70-edc1-11f0-8f07-4cf95d479851
6eee6dde-edc1-11f0-8f07-4cf95d479851
6eee6e38-edc1-11f0-8f07-4cf95d479851
6eee6e9c-edc1-11f0-8f07-4cf95d479851
6eee6f00-edc1-11f0-8f07-4cf95d479851
6eee6f64-edc1-11f0-8f07-4cf95d479851
6eee6fbe-edc1-11f0-8f07-4cf95d479851
6eee7018-edc1-11f0-8f07-4cf95d479851
6eee707c-edc1-11f0-8f07-4cf95d479851

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)

84f0681d-4900-8a00-87ea-5ce32bd83b97
6632691d-4900-8a00-87ea-5ce32bd83b97
220d6a1d-4900-8a00-87ea-5ce32bd83b97
663e6b1d-4900-8a00-87ea-5ce32bd83b97
a17e6c1d-4900-8a00-87ea-5ce32bd83b97
3ef06d1d-4900-8a00-87ea-5ce32bd83b97
56fc6e1d-4900-8a00-87ea-5ce32bd83b97
30146f1d-4900-8a00-87ea-5ce32bd83b97
6dee701d-4900-8a00-87ea-5ce32bd83b97
4e36711d-4900-8a00-87ea-5ce32bd83b97
bae0721d-4900-8a00-87ea-5ce32bd83b97
432d731d-4900-8a00-87ea-5ce32bd83b97
0d2b741d-4900-8a00-87ea-5ce32bd83b97
9c2f751d-4900-8a00-87ea-5ce32bd83b97
b787761d-4900-8a00-87ea-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: