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)

019bd4ac-5b47-7f7d-9b69-a8dbfa504cbd
019bd4ac-5b48-7182-93e8-a96ac4d6969e
019bd4ac-5b48-72d1-a3a1-f9bd894fd2fa
019bd4ac-5b48-73f8-a70d-e5de6f56ebb3
019bd4ac-5b48-7517-bf28-fec03f19c525
019bd4ac-5b48-7632-be72-c4da7fb874f9
019bd4ac-5b48-774c-9b51-f8523b6311cd
019bd4ac-5b48-7867-b7b2-18e60e1872bf
019bd4ac-5b48-7986-85c5-8d6f1eec0e67
019bd4ac-5b48-7aa8-a839-1360805c3646
019bd4ac-5b48-7bc3-af40-858946c07f5d
019bd4ac-5b48-7cde-b607-527325d38beb
019bd4ac-5b48-7dcf-a2d2-217002021b27
019bd4ac-5b48-7ef6-abf2-90737be202e2
019bd4ac-5b49-7011-976e-7aaf7e264915

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)

1f0f4f5a-02f1-69ee-845a-4cf95d479851
1f0f4f5a-02f1-6be2-845a-4cf95d479851
1f0f4f5a-02f1-6cc8-845a-4cf95d479851
1f0f4f5a-02f1-6d9a-845a-4cf95d479851
1f0f4f5a-02f1-6e62-845a-4cf95d479851
1f0f4f5a-02f1-6f2a-845a-4cf95d479851
1f0f4f5a-02f1-6ff2-845a-4cf95d479851
1f0f4f5a-02f2-60b0-845a-4cf95d479851
1f0f4f5a-02f2-616e-845a-4cf95d479851
1f0f4f5a-02f2-622c-845a-4cf95d479851
1f0f4f5a-02f2-638a-845a-4cf95d479851
1f0f4f5a-02f2-6452-845a-4cf95d479851
1f0f4f5a-02f2-6510-845a-4cf95d479851
1f0f4f5a-02f2-65ce-845a-4cf95d479851
1f0f4f5a-02f2-6682-845a-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)

73836d7b-7865-4134-9f3d-26b0c73cf644
fae62a7d-b4a6-4a4e-b22c-b4bac0ed36c2
6c224f53-2909-40ad-9277-f3092a540b86
8e39c8f1-378a-4e6d-ba6d-cf1f4ff770e5
2363d493-b6f3-47a7-9550-ddc1681b0b6c
72131667-6d40-4d37-a1d8-c8582d811c1a
3e2b8048-92e2-49f5-9f16-6c2b36c59e62
b8fa2076-efd3-41c8-b859-034d48b6641c
c7490aba-e88f-4c6e-9dd5-fdae600860d2
0e0f0fd4-be17-44a3-abdd-1aa4f37f1cf0
674d902b-5e49-42bf-aaf3-7b6fb86f4d30
8c94b931-2279-4d41-8cf6-d87a7fd0e5ae
c86c28d3-6124-46d7-8da9-fca296b467cc
50b0e48c-5b91-4564-9509-07531a439a9b
f667ef01-28da-4ad9-a2cd-95bbc9f30247

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)

a02f2baa-f4f5-11f0-845a-4cf95d479851
a02f2c04-f4f5-11f0-845a-4cf95d479851
a02f2c68-f4f5-11f0-845a-4cf95d479851
a02f2cc2-f4f5-11f0-845a-4cf95d479851
a02f2d26-f4f5-11f0-845a-4cf95d479851
a02f2d8a-f4f5-11f0-845a-4cf95d479851
a02f2dee-f4f5-11f0-845a-4cf95d479851
a02f2e5c-f4f5-11f0-845a-4cf95d479851
a02f2ec0-f4f5-11f0-845a-4cf95d479851
a02f2f1a-f4f5-11f0-845a-4cf95d479851
a02f2f7e-f4f5-11f0-845a-4cf95d479851
a02f2fe2-f4f5-11f0-845a-4cf95d479851
a02f3046-f4f5-11f0-845a-4cf95d479851
a02f30a0-f4f5-11f0-845a-4cf95d479851
a02f30fa-f4f5-11f0-845a-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)

1152022c-3a01-8301-87ea-5ce32bd83b97
d654042c-3a01-8301-87ea-5ce32bd83b97
3e15052c-3a01-8301-87ea-5ce32bd83b97
57da062c-3a01-8301-87ea-5ce32bd83b97
854f072c-3a01-8301-87ea-5ce32bd83b97
9315082c-3a01-8301-87ea-5ce32bd83b97
84a3092c-3a01-8301-87ea-5ce32bd83b97
f5440a2c-3a01-8301-87ea-5ce32bd83b97
85200b2c-3a01-8301-87ea-5ce32bd83b97
27c20c2c-3a01-8301-87ea-5ce32bd83b97
56b30d2c-3a01-8301-87ea-5ce32bd83b97
20180e2c-3a01-8301-87ea-5ce32bd83b97
faaf0f2c-3a01-8301-87ea-5ce32bd83b97
071a102c-3a01-8301-87ea-5ce32bd83b97
65ad112c-3a01-8301-87ea-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: