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)

019f4ac0-fd09-7052-97dc-e4ed0ef733d3
019f4ac0-fd0a-7200-a7ea-0f8bc92258d6
019f4ac0-fd0a-733c-8173-1968f8aceb17
019f4ac0-fd0a-745f-ba1d-7d5beeb67d29
019f4ac0-fd0a-7575-823d-eb38f6e1f320
019f4ac0-fd0a-7690-b649-b1a7e740f9cf
019f4ac0-fd0a-77a2-9344-9eb160dee4d5
019f4ac0-fd0a-78da-b0de-f714d3b5b552
019f4ac0-fd0a-79f0-8bb8-86b48162f86a
019f4ac0-fd0a-7b07-97f6-06a9e888c9ce
019f4ac0-fd0a-7c19-b969-058658b3ab7e
019f4ac0-fd0a-7d30-8845-4fc92e770756
019f4ac0-fd0a-7e42-8116-79656c80f714
019f4ac0-fd0a-7f54-906c-d5ad35c1260e
019f4ac0-fd0b-7067-8136-f878fce003a4

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)

1f17c2a2-61dc-642c-860b-4cf95d479851
1f17c2a2-61dc-65d0-860b-4cf95d479851
1f17c2a2-61dc-66b6-860b-4cf95d479851
1f17c2a2-61dc-677e-860b-4cf95d479851
1f17c2a2-61dc-6846-860b-4cf95d479851
1f17c2a2-61dc-6904-860b-4cf95d479851
1f17c2a2-61dc-69c2-860b-4cf95d479851
1f17c2a2-61dc-6a80-860b-4cf95d479851
1f17c2a2-61dc-6b3e-860b-4cf95d479851
1f17c2a2-61dc-6c06-860b-4cf95d479851
1f17c2a2-61dc-6d50-860b-4cf95d479851
1f17c2a2-61dc-6e18-860b-4cf95d479851
1f17c2a2-61dc-6ed6-860b-4cf95d479851
1f17c2a2-61dc-6f94-860b-4cf95d479851
1f17c2a2-61dd-605c-860b-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)

261dd12e-7c2a-11f1-860b-4cf95d479851
261dd192-7c2a-11f1-860b-4cf95d479851
261dd1ec-7c2a-11f1-860b-4cf95d479851
261dd246-7c2a-11f1-860b-4cf95d479851
261dd2aa-7c2a-11f1-860b-4cf95d479851
261dd30e-7c2a-11f1-860b-4cf95d479851
261dd372-7c2a-11f1-860b-4cf95d479851
261dd3cc-7c2a-11f1-860b-4cf95d479851
261dd430-7c2a-11f1-860b-4cf95d479851
261dd48a-7c2a-11f1-860b-4cf95d479851
261dd4ee-7c2a-11f1-860b-4cf95d479851
261dd548-7c2a-11f1-860b-4cf95d479851
261dd5ac-7c2a-11f1-860b-4cf95d479851
261dd606-7c2a-11f1-860b-4cf95d479851
261dd660-7c2a-11f1-860b-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)

49d28331-9001-8f0b-87ea-5ce32bd83b97
3cc58431-9001-8f0b-87ea-5ce32bd83b97
489c8531-9001-8f0b-87ea-5ce32bd83b97
34fd8731-9001-8f0b-87ea-5ce32bd83b97
7a5c8831-9001-8f0b-87ea-5ce32bd83b97
a7ca8931-9001-8f0b-87ea-5ce32bd83b97
c8ce8a31-9001-8f0b-87ea-5ce32bd83b97
7a0b8b31-9001-8f0b-87ea-5ce32bd83b97
56cf8c31-9001-8f0b-87ea-5ce32bd83b97
7f888d31-9001-8f0b-87ea-5ce32bd83b97
b28e8e31-9001-8f0b-87ea-5ce32bd83b97
17668f31-9001-8f0b-87ea-5ce32bd83b97
127d9031-9001-8f0b-87ea-5ce32bd83b97
444f9131-9001-8f0b-87ea-5ce32bd83b97
10ec9231-9001-8f0b-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)

e3242b32-bc9f-4efb-b2f9-0c3cf26827f8
2860345f-20cf-4782-b64a-2a4e7037d80f
f398043f-2412-46b7-84c2-f675f142a4b0
300cdf9b-7014-4f57-9543-bbb6302d41a4
53e924e2-0a1a-4437-9525-27298739bdab
682f9c96-b13a-4cea-84a8-ea81b510af23
de4342de-04f3-44e2-addb-53982b17aa8d
06d61248-faaf-43e7-a276-78c7411a6409
45b7cb71-6536-4990-ad44-fba1bf7c1f3a
f143dabd-b890-40fe-a92f-7aa9c4fe9ec7
79a793be-c78e-47a1-bfb1-9f3cb659a2ed
1e49b5b0-7597-4569-b138-99f3f4a4f874
cc6271ce-f833-436f-947d-6118cdf874fc
6abf501d-11ae-4596-99de-1dd5b76447c2
9ebbf223-09d5-48bb-a40c-db0a6c1df31a

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: