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)

019cebca-4bb4-713c-bcd7-0b4126b1428c
019cebca-4bb4-72d5-ab96-cfd03f824a7a
019cebca-4bb4-7419-9da8-cfbf2a9ab76b
019cebca-4bb4-753c-9d94-e1d81aee8b1b
019cebca-4bb4-7657-8084-86c257f67e33
019cebca-4bb4-776d-8bff-1041d17857be
019cebca-4bb4-7888-a631-cc638a223917
019cebca-4bb4-799e-84c5-ee82d547a737
019cebca-4bb4-7ab5-8797-d9ed29b9d66d
019cebca-4bb4-7bcb-8dba-e98e9100f8af
019cebca-4bb4-7ce6-99a3-989fb2bb3ddf
019cebca-4bb4-7dfc-9d45-4c4a1ec546bd
019cebca-4bb4-7f13-8f7b-c246cf40676d
019cebca-4bb5-702e-b1f2-5bfd412ca781
019cebca-4bb5-7144-be95-926d03185554

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)

1f11f8ca-1ae9-654e-967e-4cf95d479851
1f11f8ca-1ae9-66e8-967e-4cf95d479851
1f11f8ca-1ae9-67d8-967e-4cf95d479851
1f11f8ca-1ae9-68aa-967e-4cf95d479851
1f11f8ca-1ae9-6972-967e-4cf95d479851
1f11f8ca-1ae9-6a30-967e-4cf95d479851
1f11f8ca-1ae9-6af8-967e-4cf95d479851
1f11f8ca-1ae9-6bb6-967e-4cf95d479851
1f11f8ca-1ae9-6c74-967e-4cf95d479851
1f11f8ca-1ae9-6d3c-967e-4cf95d479851
1f11f8ca-1ae9-6e90-967e-4cf95d479851
1f11f8ca-1ae9-6f62-967e-4cf95d479851
1f11f8ca-1aea-602a-967e-4cf95d479851
1f11f8ca-1aea-60fc-967e-4cf95d479851
1f11f8ca-1aea-61c4-967e-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)

3b4d931e-c8be-432f-8e01-a61fe759ec69
3785b5fc-7f36-4987-bc2d-7de14b0e2e70
e9e4cbfd-ff15-406d-ac26-9a7ebf03cb94
449aaea3-e0db-47e0-82b5-f6307821616b
b6560ae9-84d0-4b87-ba89-f49962b9ecb9
6de1a4f4-b523-477c-8669-a98ab1b0be4d
0d76f093-6df9-4d66-951c-12b84b9db901
f5811562-7c4d-4f70-a896-4616975e5a53
c3ef09a0-76d3-492d-a570-f44e8dae0f5a
a16d9e6c-9161-41cd-8cbb-20f71ffa8cd7
0b7329a3-2341-4dc0-9c02-3ab80d910abf
dbe71d6e-3e6e-416e-bad8-d7ce321fcf83
37e7e930-9f98-4e3d-8d82-1c38ffb4aaac
645c5495-3448-4d20-946b-278ba7b1f868
08a024a3-d124-4c41-943e-4eb502f54dea

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)

a1aea6ec-1f8c-11f1-967e-4cf95d479851
a1aea750-1f8c-11f1-967e-4cf95d479851
a1aea7b4-1f8c-11f1-967e-4cf95d479851
a1aea818-1f8c-11f1-967e-4cf95d479851
a1aea87c-1f8c-11f1-967e-4cf95d479851
a1aea8e0-1f8c-11f1-967e-4cf95d479851
a1aea944-1f8c-11f1-967e-4cf95d479851
a1aea99e-1f8c-11f1-967e-4cf95d479851
a1aeaa02-1f8c-11f1-967e-4cf95d479851
a1aeaa5c-1f8c-11f1-967e-4cf95d479851
a1aeaab6-1f8c-11f1-967e-4cf95d479851
a1aeab1a-1f8c-11f1-967e-4cf95d479851
a1aeab74-1f8c-11f1-967e-4cf95d479851
a1aeabd8-1f8c-11f1-967e-4cf95d479851
a1aeac46-1f8c-11f1-967e-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)

72b25d1d-5902-8904-87ea-5ce32bd83b97
794e5e1d-5902-8904-87ea-5ce32bd83b97
d8265f1d-5902-8904-87ea-5ce32bd83b97
84aa601d-5902-8904-87ea-5ce32bd83b97
b706621d-5902-8904-87ea-5ce32bd83b97
8328631d-5902-8904-87ea-5ce32bd83b97
32f0641d-5902-8904-87ea-5ce32bd83b97
85a4651d-5902-8904-87ea-5ce32bd83b97
79b8661d-5902-8904-87ea-5ce32bd83b97
f0f3671d-5902-8904-87ea-5ce32bd83b97
e56c681d-5902-8904-87ea-5ce32bd83b97
1e0d691d-5902-8904-87ea-5ce32bd83b97
e5676a1d-5902-8904-87ea-5ce32bd83b97
61346b1d-5902-8904-87ea-5ce32bd83b97
e3746c1d-5902-8904-87ea-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: