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)

018f13d3-a428-73f4-a9ed-1ba7ee6d6b61
018f13d3-a428-7575-a5ab-5293c216fc38
018f13d3-a428-76b9-a31c-dbfa0a26370a
018f13d3-a428-77dc-b752-1c9fe3796a56
018f13d3-a428-78fe-8c1e-dfbd34f64d44
018f13d3-a428-7a19-b178-d1b1971ed512
018f13d3-a428-7b38-b6c1-26e05290dda6
018f13d3-a428-7c52-a9cd-8647b27f85f4
018f13d3-a428-7d71-8230-a50ee9f0e648
018f13d3-a428-7e8c-81cd-ee926cd09359
018f13d3-a428-7faf-9d69-b41bfb42a933
018f13d3-a429-7077-816f-63866ef76565
018f13d3-a429-719a-a7b8-ee0a1358f6df
018f13d3-a429-72bd-90a5-f056773b3d75
018f13d3-a429-73dc-83f4-5ba415970677

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)

1ef02c88-ebdc-6ef6-a944-4cf95d479851
1ef02c88-ebdd-60a4-a944-4cf95d479851
1ef02c88-ebdd-6180-a944-4cf95d479851
1ef02c88-ebdd-6252-a944-4cf95d479851
1ef02c88-ebdd-631a-a944-4cf95d479851
1ef02c88-ebdd-63d8-a944-4cf95d479851
1ef02c88-ebdd-64a0-a944-4cf95d479851
1ef02c88-ebdd-655e-a944-4cf95d479851
1ef02c88-ebdd-661c-a944-4cf95d479851
1ef02c88-ebdd-66da-a944-4cf95d479851
1ef02c88-ebdd-687e-a944-4cf95d479851
1ef02c88-ebdd-69f0-a944-4cf95d479851
1ef02c88-ebdd-6b30-a944-4cf95d479851
1ef02c88-ebdd-6c66-a944-4cf95d479851
1ef02c88-ebdd-6da6-a944-4cf95d479851

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)

81c8b524-f90b-430d-bb63-c8dbc5832430
e604f375-48ad-467f-805a-4a437950b0bd
9e16f5e8-7485-445b-81c9-cea926553b40
7e3ea9a8-9dda-4b34-bfa6-ea731734d79b
b6ed469d-7117-4807-abf2-02cd5e8e94d3
752ffc45-8326-45e5-8f6d-39c02defe09e
5c7c4f4e-8dc0-4be2-a577-274197fa57a8
50e92292-978d-48db-bb50-e480c02950d1
8bbbc6a7-a46a-40b3-8a40-79c33bb63097
16c94c76-d5ce-4487-bfbb-dc915a402431
972b5717-1eaf-4924-b16e-dac6249f133f
87aaf2cd-4c15-4767-b67a-b5adbc8a78cb
8d32f777-baaf-431e-9c70-b9671ab77bf4
126f788e-c47a-4ac0-a5cc-9fc67a85ded4
1c671dfe-ef14-4005-aebb-0018f8905789

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)

8ebde3f0-02c8-11ef-a944-4cf95d479851
8ebde454-02c8-11ef-a944-4cf95d479851
8ebde4b8-02c8-11ef-a944-4cf95d479851
8ebde526-02c8-11ef-a944-4cf95d479851
8ebde580-02c8-11ef-a944-4cf95d479851
8ebde5e4-02c8-11ef-a944-4cf95d479851
8ebde648-02c8-11ef-a944-4cf95d479851
8ebde6ac-02c8-11ef-a944-4cf95d479851
8ebde710-02c8-11ef-a944-4cf95d479851
8ebde76a-02c8-11ef-a944-4cf95d479851
8ebde7d8-02c8-11ef-a944-4cf95d479851
8ebde832-02c8-11ef-a944-4cf95d479851
8ebde8a0-02c8-11ef-a944-4cf95d479851
8ebde904-02c8-11ef-a944-4cf95d479851
8ebde968-02c8-11ef-a944-4cf95d479851

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)

3c92541c-0165-8074-87e8-5ce32bd83b96
5636551c-0165-8074-87e8-5ce32bd83b96
9f8f561c-0165-8074-87e8-5ce32bd83b96
6c1c571c-0165-8074-87e8-5ce32bd83b96
74c6581c-0165-8074-87e8-5ce32bd83b96
5da1591c-0165-8074-87e8-5ce32bd83b96
0e115a1c-0165-8074-87e8-5ce32bd83b96
2f295b1c-0165-8074-87e8-5ce32bd83b96
d6ae5c1c-0165-8074-87e8-5ce32bd83b96
3fbe5d1c-0165-8074-87e8-5ce32bd83b96
df8f5e1c-0165-8074-87e8-5ce32bd83b96
b1245f1c-0165-8074-87e8-5ce32bd83b96
ab24611c-0165-8074-87e8-5ce32bd83b96
94b8621c-0165-8074-87e8-5ce32bd83b96
5e62631c-0165-8074-87e8-5ce32bd83b96

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: