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)

0190f35d-2ba0-77f4-ab4f-6bc213ada14f
0190f35d-2ba0-7982-99a2-9ebc321f8192
0190f35d-2ba0-7ac1-bb2c-8368991b5638
0190f35d-2ba0-7be4-86c6-ae07a2df1f2a
0190f35d-2ba0-7cfe-9b62-749c57126ddd
0190f35d-2ba0-7e19-b3e3-47bc61d46cfd
0190f35d-2ba0-7f34-b900-091111eb3466
0190f35d-2ba1-7077-8d26-eaf06e3fbed8
0190f35d-2ba1-71b3-9672-08c8f8550956
0190f35d-2ba1-72cd-9a88-31879c4b1846
0190f35d-2ba1-73e8-8c8d-942395a0ef68
0190f35d-2ba1-7503-be7d-602da1c2af8e
0190f35d-2ba1-7621-b009-cc86a5e7c97d
0190f35d-2ba1-773c-a037-78d9ca4d736d
0190f35d-2ba1-7852-be99-a7305489fe09

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)

1ef4bf47-af99-6948-ae9e-4cf95d479851
1ef4bf47-af99-6ae2-ae9e-4cf95d479851
1ef4bf47-af99-6bdc-ae9e-4cf95d479851
1ef4bf47-af99-6cb8-ae9e-4cf95d479851
1ef4bf47-af99-6d8a-ae9e-4cf95d479851
1ef4bf47-af99-6e5c-ae9e-4cf95d479851
1ef4bf47-af99-6f24-ae9e-4cf95d479851
1ef4bf47-af99-6ff6-ae9e-4cf95d479851
1ef4bf47-af9a-60be-ae9e-4cf95d479851
1ef4bf47-af9a-6186-ae9e-4cf95d479851
1ef4bf47-af9a-6302-ae9e-4cf95d479851
1ef4bf47-af9a-647e-ae9e-4cf95d479851
1ef4bf47-af9a-65aa-ae9e-4cf95d479851
1ef4bf47-af9a-667c-ae9e-4cf95d479851
1ef4bf47-af9a-6744-ae9e-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)

b5960cc4-772c-4f09-af5a-0dd191f4e38c
5f89dd59-30b9-40d6-b598-2cd2d25e6357
b9448131-baff-4670-8617-cc0106d4d04d
8b17aac7-da58-45c9-98a5-52ec35e46ac0
4df899e7-93ff-4340-9c9a-fa21723490c0
28c0a16f-38a2-4632-8fc6-0a8e7f942208
b0697683-0765-4849-9f0e-ce77aa70c1b8
cdc065fe-c619-4cc9-ab10-b8590b49961b
d812b92f-c961-4f70-83ce-d0186cec2064
c272b653-d137-4967-940a-ddfed53539a4
0e9db38c-75e7-462b-9588-fca5d6d73409
0708538e-88c0-4b23-baf6-85a36d9357d9
e4ce7272-506d-41d3-8c83-6a8b1a61cb57
03298a42-d5b4-43c4-8034-039856b0c3b1
12ba22cf-2d48-4627-8687-f94d20d673cb

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)

7af9ac80-4bf4-11ef-ae9e-4cf95d479851
7af9acee-4bf4-11ef-ae9e-4cf95d479851
7af9ad5c-4bf4-11ef-ae9e-4cf95d479851
7af9adc0-4bf4-11ef-ae9e-4cf95d479851
7af9ae2e-4bf4-11ef-ae9e-4cf95d479851
7af9ae92-4bf4-11ef-ae9e-4cf95d479851
7af9aef6-4bf4-11ef-ae9e-4cf95d479851
7af9af64-4bf4-11ef-ae9e-4cf95d479851
7af9afd2-4bf4-11ef-ae9e-4cf95d479851
7af9b036-4bf4-11ef-ae9e-4cf95d479851
7af9b0a4-4bf4-11ef-ae9e-4cf95d479851
7af9b0fe-4bf4-11ef-ae9e-4cf95d479851
7af9b16c-4bf4-11ef-ae9e-4cf95d479851
7af9b1da-4bf4-11ef-ae9e-4cf95d479851
7af9b23e-4bf4-11ef-ae9e-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

24c1e72f-020d-80d1-87e8-5ce32bd83b96
8632e82f-020d-80d1-87e8-5ce32bd83b96
e1a3e92f-020d-80d1-87e8-5ce32bd83b96
8e84ea2f-020d-80d1-87e8-5ce32bd83b96
6296eb2f-020d-80d1-87e8-5ce32bd83b96
92ccec2f-020d-80d1-87e8-5ce32bd83b96
bf88ed2f-020d-80d1-87e8-5ce32bd83b96
f6b2ee2f-020d-80d1-87e8-5ce32bd83b96
e0ccef2f-020d-80d1-87e8-5ce32bd83b96
6fcff12f-020d-80d1-87e8-5ce32bd83b96
b078f22f-020d-80d1-87e8-5ce32bd83b96
4459f32f-020d-80d1-87e8-5ce32bd83b96
1e41f42f-020d-80d1-87e8-5ce32bd83b96
4c96f52f-020d-80d1-87e8-5ce32bd83b96
3870f62f-020d-80d1-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: