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)

019bdde4-7372-79bf-9cd0-4f200911f7a5
019bdde4-7372-7b75-895c-ab77b8007d35
019bdde4-7372-7cb9-8e58-b4251d97aa7c
019bdde4-7372-7ddc-a0bd-2c880df68d30
019bdde4-7372-7ef6-882a-1d049132388d
019bdde4-7373-7011-bc07-c05975cf4ff2
019bdde4-7373-7130-96c8-835de28102e5
019bdde4-7373-724a-b7f0-9ac0391f6330
019bdde4-7373-7365-b6b7-9be9c85e0b24
019bdde4-7373-747f-8915-16f6fcd5bd1f
019bdde4-7373-75cb-b7f4-e3f19e97ac4a
019bdde4-7373-76ee-8f2c-8f2a0cfedcee
019bdde4-7373-7809-a381-96cf95a93ab4
019bdde4-7373-7923-a425-a0357db89deb
019bdde4-7373-7a3e-a6b1-5ed1e5e27a27

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)

1f0f65db-f5f1-6a94-8f2a-4cf95d479851
1f0f65db-f5f1-6c38-8f2a-4cf95d479851
1f0f65db-f5f1-6d32-8f2a-4cf95d479851
1f0f65db-f5f1-6e0e-8f2a-4cf95d479851
1f0f65db-f5f1-6ee0-8f2a-4cf95d479851
1f0f65db-f5f1-6fa8-8f2a-4cf95d479851
1f0f65db-f5f2-6070-8f2a-4cf95d479851
1f0f65db-f5f2-6138-8f2a-4cf95d479851
1f0f65db-f5f2-61f6-8f2a-4cf95d479851
1f0f65db-f5f2-62c8-8f2a-4cf95d479851
1f0f65db-f5f2-6408-8f2a-4cf95d479851
1f0f65db-f5f2-64da-8f2a-4cf95d479851
1f0f65db-f5f2-65a2-8f2a-4cf95d479851
1f0f65db-f5f2-666a-8f2a-4cf95d479851
1f0f65db-f5f2-6732-8f2a-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)

ac1aeb80-1b42-403f-9ba8-95dfee161ec6
47543c9e-7d10-4ecd-a672-15dcea319e2c
0512a145-da55-4e8f-8933-eb801d19f0d0
d038af2d-b4e2-4750-8087-2baa571c6ad0
28c7cad5-dfb5-4151-a053-df7480aaf7a6
50a1b846-7450-410d-9644-312635721bbe
ed0ded2a-a0e7-4c1d-a39e-d9b561ac554a
d9e4fbe7-bfe1-4b4f-a4f2-0c3eeb96748e
4e999d31-6473-4474-9840-8370de141273
14fd5ffd-38c5-4838-a362-843d9b111403
61125f97-3d34-403c-b1b3-4a38d5d1e19e
5df4f156-85a4-4595-9a87-a36be7faaadd
a9ce5cdc-2797-4c7b-a1de-9d024366fb22
278b150f-b203-4abe-a94d-906ec31e8e15
34b50b9b-ec39-4758-a8eb-7088d874a8ad

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)

bf5f2c50-f65d-11f0-8f2a-4cf95d479851
bf5f2cb4-f65d-11f0-8f2a-4cf95d479851
bf5f2d0e-f65d-11f0-8f2a-4cf95d479851
bf5f2d7c-f65d-11f0-8f2a-4cf95d479851
bf5f2de0-f65d-11f0-8f2a-4cf95d479851
bf5f2e3a-f65d-11f0-8f2a-4cf95d479851
bf5f2e9e-f65d-11f0-8f2a-4cf95d479851
bf5f2f02-f65d-11f0-8f2a-4cf95d479851
bf5f2f70-f65d-11f0-8f2a-4cf95d479851
bf5f2fd4-f65d-11f0-8f2a-4cf95d479851
bf5f3038-f65d-11f0-8f2a-4cf95d479851
bf5f309c-f65d-11f0-8f2a-4cf95d479851
bf5f3100-f65d-11f0-8f2a-4cf95d479851
bf5f315a-f65d-11f0-8f2a-4cf95d479851
bf5f31be-f65d-11f0-8f2a-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)

196f2823-0c00-8501-87ea-5ce32bd83b97
5ced2923-0c00-8501-87ea-5ce32bd83b97
31042a23-0c00-8501-87ea-5ce32bd83b97
00462b23-0c00-8501-87ea-5ce32bd83b97
edf82c23-0c00-8501-87ea-5ce32bd83b97
de382d23-0c00-8501-87ea-5ce32bd83b97
a6332e23-0c00-8501-87ea-5ce32bd83b97
f7342f23-0c00-8501-87ea-5ce32bd83b97
bb9b3023-0c00-8501-87ea-5ce32bd83b97
93ef3123-0c00-8501-87ea-5ce32bd83b97
adb93223-0c00-8501-87ea-5ce32bd83b97
4d833323-0c00-8501-87ea-5ce32bd83b97
426d3423-0c00-8501-87ea-5ce32bd83b97
81dc3523-0c00-8501-87ea-5ce32bd83b97
ad4b3623-0c00-8501-87ea-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: