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)

01948e19-a4db-7103-bc7a-903f2e4ceeab
01948e19-a4db-72c5-bfb0-2541168aa617
01948e19-a4db-7419-8660-7e0140c95e24
01948e19-a4db-753c-8b61-97b4ef2ecfd5
01948e19-a4db-765b-ae8f-acafef18f9ba
01948e19-a4db-7775-9a63-ca2bc9786cfe
01948e19-a4db-7890-93d2-46a1608e06a7
01948e19-a4db-79aa-b7da-0cb9d1140f55
01948e19-a4db-7ac5-adcd-5fcfe6394829
01948e19-a4db-7be0-aa66-6d75874026f4
01948e19-a4db-7d0b-a94d-086c372ea064
01948e19-a4db-7e32-a345-abb358c72b84
01948e19-a4db-7f48-ab89-f92681a9385c
01948e19-a4dc-70de-90a3-2c7151805dd4
01948e19-a4dc-7232-b782-b3daccfa8323

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)

1efd8c0d-d391-6c9c-a73b-4cf95d479851
1efd8c0d-d391-6e54-a73b-4cf95d479851
1efd8c0d-d391-6f44-a73b-4cf95d479851
1efd8c0d-d392-600c-a73b-4cf95d479851
1efd8c0d-d392-60d4-a73b-4cf95d479851
1efd8c0d-d392-6192-a73b-4cf95d479851
1efd8c0d-d392-625a-a73b-4cf95d479851
1efd8c0d-d392-6318-a73b-4cf95d479851
1efd8c0d-d392-63e0-a73b-4cf95d479851
1efd8c0d-d392-649e-a73b-4cf95d479851
1efd8c0d-d392-65de-a73b-4cf95d479851
1efd8c0d-d392-66ba-a73b-4cf95d479851
1efd8c0d-d392-6778-a73b-4cf95d479851
1efd8c0d-d392-6840-a73b-4cf95d479851
1efd8c0d-d392-68fe-a73b-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)

4c2b2f3f-7266-4143-82d6-e0e76e53e9fc
a2d80a1f-1bd9-4ec9-8f79-baffdcc52577
79c4007b-9ee0-4a98-98d6-597d73397412
45e76df5-3308-4c26-8fd0-776434e0e0e8
b909ba0e-98a2-4348-ac81-2034c9b29cdc
f9831060-81d9-40ff-b1cd-e1474c6662dd
94baef9c-d24e-4366-bec4-f41562ca9c9f
035c55a1-bb07-49c1-93a1-e5d032566286
daa8eefa-e0db-452b-a243-84da698d0583
5f9af762-64c4-47a8-b8e7-800724644609
1050e166-1aaa-483f-a40b-cb827f7279b8
6e8e34d0-c65c-429c-8f6d-7bcf09581158
d4f4df57-038b-48fd-b75d-2172e0208646
15463482-9eb3-4fe4-8c28-06da9868d509
4c2f32b8-94a9-4c25-86d6-1a8ebb872690

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)

dd392e1c-d8c0-11ef-a73b-4cf95d479851
dd392e8a-d8c0-11ef-a73b-4cf95d479851
dd392ee4-d8c0-11ef-a73b-4cf95d479851
dd392f52-d8c0-11ef-a73b-4cf95d479851
dd392fb6-d8c0-11ef-a73b-4cf95d479851
dd39301a-d8c0-11ef-a73b-4cf95d479851
dd393074-d8c0-11ef-a73b-4cf95d479851
dd3930d8-d8c0-11ef-a73b-4cf95d479851
dd39313c-d8c0-11ef-a73b-4cf95d479851
dd3931a0-d8c0-11ef-a73b-4cf95d479851
dd3931fa-d8c0-11ef-a73b-4cf95d479851
dd39325e-d8c0-11ef-a73b-4cf95d479851
dd3932c2-d8c0-11ef-a73b-4cf95d479851
dd39331c-d8c0-11ef-a73b-4cf95d479851
dd393376-d8c0-11ef-a73b-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)

be16dc20-030d-8016-87e9-5ce32bd83b96
2553dd20-030d-8016-87e9-5ce32bd83b96
7da1de20-030d-8016-87e9-5ce32bd83b96
03e8df20-030d-8016-87e9-5ce32bd83b96
971ee020-030d-8016-87e9-5ce32bd83b96
cdf7e120-030d-8016-87e9-5ce32bd83b96
d50fe220-030d-8016-87e9-5ce32bd83b96
09e2e320-030d-8016-87e9-5ce32bd83b96
504ce420-030d-8016-87e9-5ce32bd83b96
2a4ae520-030d-8016-87e9-5ce32bd83b96
f15fe620-030d-8016-87e9-5ce32bd83b96
7a8de720-030d-8016-87e9-5ce32bd83b96
58d0e820-030d-8016-87e9-5ce32bd83b96
2c63e920-030d-8016-87e9-5ce32bd83b96
796dea20-030d-8016-87e9-5ce32bd83b96

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: