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)

018f1af3-ca12-70d5-bf1c-489b4c6e2193
018f1af3-ca12-726f-bd77-e1eb6f62d55b
018f1af3-ca12-73b7-b29f-28c3fcc5752b
018f1af3-ca12-74da-8569-05e77699357d
018f1af3-ca12-75f4-b845-4ddbea1bca1b
018f1af3-ca12-7713-925c-221cf6a6370e
018f1af3-ca12-7832-8957-964b15bf0734
018f1af3-ca12-794c-be91-0ca632af01e9
018f1af3-ca12-7a6b-819e-454c2823ccaf
018f1af3-ca12-7b82-a0c6-7c9dcd187b01
018f1af3-ca12-7c9c-acdc-35a654e5ee8c
018f1af3-ca12-7db7-9afc-1e40c3d8e3a2
018f1af3-ca12-7ed1-a81c-40159ff39ba8
018f1af3-ca12-7fec-940f-9a7afe47ac6a
018f1af3-ca13-7107-9902-9d1c6bdb9561

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)

1ef03dee-686c-6cc0-8da4-4cf95d479851
1ef03dee-686c-6e6e-8da4-4cf95d479851
1ef03dee-686c-6f54-8da4-4cf95d479851
1ef03dee-686d-6026-8da4-4cf95d479851
1ef03dee-686d-60f8-8da4-4cf95d479851
1ef03dee-686d-61b6-8da4-4cf95d479851
1ef03dee-686d-627e-8da4-4cf95d479851
1ef03dee-686d-633c-8da4-4cf95d479851
1ef03dee-686d-6404-8da4-4cf95d479851
1ef03dee-686d-64c2-8da4-4cf95d479851
1ef03dee-686d-660c-8da4-4cf95d479851
1ef03dee-686d-66de-8da4-4cf95d479851
1ef03dee-686d-679c-8da4-4cf95d479851
1ef03dee-686d-6864-8da4-4cf95d479851
1ef03dee-686d-6922-8da4-4cf95d479851

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)

0f323ea9-36cb-44e0-91d0-7e3d6260e47f
dc98ed9b-1c60-46c6-aa9d-db2cf5abe213
17274812-2ba2-4d54-b8f1-4f516bbb326d
ed5b52ad-4b44-4982-aa08-b742d89c3bc3
1931535c-5c6f-44f4-b510-4b7a84a03fee
1e8daf42-99d8-429a-999b-f467556b27bd
d409bc0a-afcb-41af-a819-ccee72ba7ab7
ddf3fe85-de35-4e04-8ae2-5f0cbd8651ef
07981fd7-5482-46d2-b4ae-107fe3b992e8
454925a8-4112-4048-b40d-68939c5bdb31
09315402-60b2-45c4-a135-53c4f2335bfc
0fd332e9-f39e-4fe3-a71c-d068e74d6d41
e4c7b13a-196c-465c-b61a-57ad6a7984c4
ea24e985-a1e1-4b51-9a08-8330acd61c87
1c2b0282-20fc-45c8-84e5-924b605f4968

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)

e686de4a-03de-11ef-8da4-4cf95d479851
e686deb8-03de-11ef-8da4-4cf95d479851
e686df1c-03de-11ef-8da4-4cf95d479851
e686df80-03de-11ef-8da4-4cf95d479851
e686dfe4-03de-11ef-8da4-4cf95d479851
e686e03e-03de-11ef-8da4-4cf95d479851
e686e0a2-03de-11ef-8da4-4cf95d479851
e686e106-03de-11ef-8da4-4cf95d479851
e686e174-03de-11ef-8da4-4cf95d479851
e686e1d8-03de-11ef-8da4-4cf95d479851
e686e23c-03de-11ef-8da4-4cf95d479851
e686e296-03de-11ef-8da4-4cf95d479851
e686e2f0-03de-11ef-8da4-4cf95d479851
e686e354-03de-11ef-8da4-4cf95d479851
e686e3b8-03de-11ef-8da4-4cf95d479851

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)

2324b237-038d-8075-87e8-5ce32bd83b96
7f82b337-038d-8075-87e8-5ce32bd83b96
7ae8b537-038d-8075-87e8-5ce32bd83b96
8d52b637-038d-8075-87e8-5ce32bd83b96
86dfb737-038d-8075-87e8-5ce32bd83b96
090ab837-038d-8075-87e8-5ce32bd83b96
7125b937-038d-8075-87e8-5ce32bd83b96
ba46ba37-038d-8075-87e8-5ce32bd83b96
0ec2bb37-038d-8075-87e8-5ce32bd83b96
c707bc37-038d-8075-87e8-5ce32bd83b96
f51abd37-038d-8075-87e8-5ce32bd83b96
d646be37-038d-8075-87e8-5ce32bd83b96
b291bf37-038d-8075-87e8-5ce32bd83b96
7d9ec037-038d-8075-87e8-5ce32bd83b96
8eccc137-038d-8075-87e8-5ce32bd83b96

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: