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)

019c88c4-0d04-76a4-b4af-7c0079517380
019c88c4-0d04-78d1-a45d-8fe8232017f7
019c88c4-0d04-7a1d-941d-762e170fda0a
019c88c4-0d04-7b3c-b339-444289a3360a
019c88c4-0d04-7c5b-b53c-40a9bad8a4eb
019c88c4-0d04-7d75-af5e-4e7fba50f01a
019c88c4-0d04-7e90-bc7b-c03fc9d0e887
019c88c4-0d04-7fa6-9a90-25b349492ea2
019c88c4-0d05-70b9-8521-c954ea463a50
019c88c4-0d05-71cf-8423-43121686f5ca
019c88c4-0d05-72e6-87a4-2357f8f59e71
019c88c4-0d05-73fc-a685-02daa3210bfc
019c88c4-0d05-7513-b785-7b1f624c75ce
019c88c4-0d05-7629-800c-e41c43c0b5fa
019c88c4-0d05-7740-9572-6e45e8569683

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)

1f110707-dbde-6a70-97ce-4cf95d479851
1f110707-dbde-6c50-97ce-4cf95d479851
1f110707-dbde-6d36-97ce-4cf95d479851
1f110707-dbde-6e08-97ce-4cf95d479851
1f110707-dbde-6eda-97ce-4cf95d479851
1f110707-dbde-6fa2-97ce-4cf95d479851
1f110707-dbdf-6060-97ce-4cf95d479851
1f110707-dbdf-6128-97ce-4cf95d479851
1f110707-dbdf-61e6-97ce-4cf95d479851
1f110707-dbdf-62a4-97ce-4cf95d479851
1f110707-dbdf-6434-97ce-4cf95d479851
1f110707-dbdf-64fc-97ce-4cf95d479851
1f110707-dbdf-65ce-97ce-4cf95d479851
1f110707-dbdf-668c-97ce-4cf95d479851
1f110707-dbdf-675e-97ce-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)

245d38e2-6d3a-4768-9353-1007ec32f4c4
4dcaa39d-97ee-4b0a-b18c-c590409e724d
2b99895b-42d6-4c07-be7f-44ba65bb12d4
b4d485ec-420e-4f97-9336-a78fb25bb3fe
d1b09289-fccc-47a7-a93b-d0d090ea7091
2d94b359-e5c0-42d5-8570-3d35520806c0
a1105fa8-810a-4034-896b-c4d7de0c7c83
206f26ad-9818-4290-871a-4c0e27f877e5
08180007-7c66-42e9-a731-c3254b7893ea
c8b28e55-7ea9-4c4a-bf74-b481aba29849
53ce9092-bdec-4721-895c-98fbcd69a590
2f1af14c-c638-4c1e-a7fe-715ebe97c9d9
9d32d1d3-16f3-4645-a586-28f3eb4d8019
2b513e6e-ca14-4f1c-b8c2-5962b43b760a
fe7d0086-268b-4b82-a565-81dabe6cd03a

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)

7dbdfc72-1070-11f1-97ce-4cf95d479851
7dbdfce0-1070-11f1-97ce-4cf95d479851
7dbdfd44-1070-11f1-97ce-4cf95d479851
7dbdfda8-1070-11f1-97ce-4cf95d479851
7dbdfe16-1070-11f1-97ce-4cf95d479851
7dbdfe70-1070-11f1-97ce-4cf95d479851
7dbdfed4-1070-11f1-97ce-4cf95d479851
7dbdff38-1070-11f1-97ce-4cf95d479851
7dbdff9c-1070-11f1-97ce-4cf95d479851
7dbdfff6-1070-11f1-97ce-4cf95d479851
7dbe005a-1070-11f1-97ce-4cf95d479851
7dbe00be-1070-11f1-97ce-4cf95d479851
7dbe0118-1070-11f1-97ce-4cf95d479851
7dbe0186-1070-11f1-97ce-4cf95d479851
7dbe01f4-1070-11f1-97ce-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)

84edb70f-1001-8603-87ea-5ce32bd83b97
f0d7b80f-1001-8603-87ea-5ce32bd83b97
fbb5b90f-1001-8603-87ea-5ce32bd83b97
3fc0ba0f-1001-8603-87ea-5ce32bd83b97
c36cbb0f-1001-8603-87ea-5ce32bd83b97
67a6bc0f-1001-8603-87ea-5ce32bd83b97
e173bd0f-1001-8603-87ea-5ce32bd83b97
33a7be0f-1001-8603-87ea-5ce32bd83b97
ffa8c00f-1001-8603-87ea-5ce32bd83b97
45abc10f-1001-8603-87ea-5ce32bd83b97
1d2ac20f-1001-8603-87ea-5ce32bd83b97
31aac30f-1001-8603-87ea-5ce32bd83b97
ea25c40f-1001-8603-87ea-5ce32bd83b97
3e29c50f-1001-8603-87ea-5ce32bd83b97
e254c60f-1001-8603-87ea-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: