UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f1501-1b5a-7d0f-9615-03a3afb4b8f3
019f1501-1b5a-7ead-b69f-c00c729a83bf
019f1501-1b5a-7fe8-9b1b-546e2b062168
019f1501-1b5b-7107-a931-ded6bd5324f5
019f1501-1b5b-721d-802e-be400030cfff
019f1501-1b5b-7338-9eed-d3b1128427d5
019f1501-1b5b-745b-b1f9-b2eb3c060b21
019f1501-1b5b-7571-a5c6-c451aa99e346
019f1501-1b5b-7688-a7e4-f0df50f10d37
019f1501-1b5b-779e-99f1-caef58e61d69
019f1501-1b5b-78b9-9cda-5d4d9f49d9d3
019f1501-1b5b-79cf-9596-277ae41d3b98
019f1501-1b5b-7ae6-a3f8-ac20b2d32c4f
019f1501-1b5b-7bf8-bdfc-be8edf28495b
019f1501-1b5b-7d0f-9578-d889452a35fd

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)

1f173f68-ebdf-67d6-9c0e-4cf95d479851
1f173f68-ebdf-6984-9c0e-4cf95d479851
1f173f68-ebdf-6a74-9c0e-4cf95d479851
1f173f68-ebdf-6b3c-9c0e-4cf95d479851
1f173f68-ebdf-6c04-9c0e-4cf95d479851
1f173f68-ebdf-6cc2-9c0e-4cf95d479851
1f173f68-ebdf-6d8a-9c0e-4cf95d479851
1f173f68-ebdf-6e48-9c0e-4cf95d479851
1f173f68-ebdf-6f06-9c0e-4cf95d479851
1f173f68-ebdf-6fc4-9c0e-4cf95d479851
1f173f68-ebe0-6104-9c0e-4cf95d479851
1f173f68-ebe0-61cc-9c0e-4cf95d479851
1f173f68-ebe0-628a-9c0e-4cf95d479851
1f173f68-ebe0-633e-9c0e-4cf95d479851
1f173f68-ebe0-63fc-9c0e-4cf95d479851

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)

8ebe04c4-73f6-11f1-9c0e-4cf95d479851
8ebe0528-73f6-11f1-9c0e-4cf95d479851
8ebe0582-73f6-11f1-9c0e-4cf95d479851
8ebe05e6-73f6-11f1-9c0e-4cf95d479851
8ebe0640-73f6-11f1-9c0e-4cf95d479851
8ebe069a-73f6-11f1-9c0e-4cf95d479851
8ebe06fe-73f6-11f1-9c0e-4cf95d479851
8ebe0758-73f6-11f1-9c0e-4cf95d479851
8ebe07bc-73f6-11f1-9c0e-4cf95d479851
8ebe0816-73f6-11f1-9c0e-4cf95d479851
8ebe087a-73f6-11f1-9c0e-4cf95d479851
8ebe08d4-73f6-11f1-9c0e-4cf95d479851
8ebe092e-73f6-11f1-9c0e-4cf95d479851
8ebe0992-73f6-11f1-9c0e-4cf95d479851
8ebe0a00-73f6-11f1-9c0e-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

2c7dea15-bb04-840b-87ea-5ce32bd83b97
a5b1eb15-bb04-840b-87ea-5ce32bd83b97
a098ec15-bb04-840b-87ea-5ce32bd83b97
2deded15-bb04-840b-87ea-5ce32bd83b97
0415ee15-bb04-840b-87ea-5ce32bd83b97
f7d2ef15-bb04-840b-87ea-5ce32bd83b97
c7fbf015-bb04-840b-87ea-5ce32bd83b97
e39cf115-bb04-840b-87ea-5ce32bd83b97
6807f215-bb04-840b-87ea-5ce32bd83b97
fbd0f315-bb04-840b-87ea-5ce32bd83b97
fd67f415-bb04-840b-87ea-5ce32bd83b97
3ccbf515-bb04-840b-87ea-5ce32bd83b97
8b2af615-bb04-840b-87ea-5ce32bd83b97
08f1f715-bb04-840b-87ea-5ce32bd83b97
add7f815-bb04-840b-87ea-5ce32bd83b97

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)

abd8c690-742e-4f68-a26d-1efd67b69b82
e2522cc5-037b-47ca-a5c9-a2d6b3c605d7
433c9642-c218-40a8-b07c-6d0fb9969b44
a8b8b5cb-aa3c-46fb-8167-01f06a0be21e
b4dcb0d5-4d43-43e4-ba88-d417674c0613
19f8c12d-e267-408b-a40c-c7d46e42632d
0bdea0ce-d971-412a-be35-dd772b55e7c5
778c7bc8-7bc0-4c2f-a0d8-776a56949d12
20039b20-d081-45d2-b923-c9dd8fff9a03
7adafad9-8ec0-4b4e-9366-a75e84d4c50a
dc0ce9d9-019d-489b-b104-7376250f89d4
55df040a-4900-4c6f-8624-a3e01725abde
93270637-2daf-48ad-9998-17a91cac329b
5812b334-5b35-48cf-9391-e4b266ccbcc6
8b8264d5-8fa0-435f-a7b7-5067a4d1d781

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: