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)

019cef0d-f527-7faa-be91-79401d70b648
019cef0d-f528-71d8-b8da-d8dc1a128235
019cef0d-f528-732c-8d71-458aeb625f20
019cef0d-f528-744e-8bc8-1e61846ec5ef
019cef0d-f528-7571-8f6d-49022eacec0f
019cef0d-f528-7690-92d6-75a9255543e1
019cef0d-f528-77af-b983-b2aa9eb7da02
019cef0d-f528-78c9-914d-c0f52baa4526
019cef0d-f528-79e8-a51a-b2b663cb03e5
019cef0d-f528-7b07-8440-fc53c2fa3f13
019cef0d-f528-7c25-80d7-48c80106c3db
019cef0d-f528-7d48-a4ef-a4fc13629f2e
019cef0d-f528-7e67-8bfb-353804eb8d50
019cef0d-f528-7f82-9851-539b728b877f
019cef0d-f529-70a0-b3e7-3693c601cf7d

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)

1f1200c2-4b9d-6758-a987-4cf95d479851
1f1200c2-4b9d-6956-a987-4cf95d479851
1f1200c2-4b9d-6a46-a987-4cf95d479851
1f1200c2-4b9d-6b18-a987-4cf95d479851
1f1200c2-4b9d-6be0-a987-4cf95d479851
1f1200c2-4b9d-6ca8-a987-4cf95d479851
1f1200c2-4b9d-6d70-a987-4cf95d479851
1f1200c2-4b9d-6e2e-a987-4cf95d479851
1f1200c2-4b9d-6ef6-a987-4cf95d479851
1f1200c2-4b9d-6fbe-a987-4cf95d479851
1f1200c2-4b9e-6130-a987-4cf95d479851
1f1200c2-4b9e-620c-a987-4cf95d479851
1f1200c2-4b9e-62ca-a987-4cf95d479851
1f1200c2-4b9e-6388-a987-4cf95d479851
1f1200c2-4b9e-6450-a987-4cf95d479851

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)

b617a4ce-2f77-4645-adb1-63bf939b245b
09ea20d6-ef0b-4a0b-9659-db55d46ac289
2460eeee-dca4-4810-9382-b9839d47d75d
56ef6cf5-6bd7-4194-9b18-64bd9c1d5e86
3b07dd12-e09e-433d-84ec-cc5d125b7d7a
bcd50b1f-5242-4954-b536-84369b54c4a9
e56d2528-6334-4c54-beb2-ab69f199f498
d2bb798e-49d9-48a3-9330-9eb55e685893
a61ad0fa-a2e5-4cf0-8d64-e3d46503dcd3
7d31c7d4-108d-4996-b79b-0f2cf18ad2a2
3dfa68df-0d64-4827-a504-363d66f759cc
e008f86a-6b8f-4e0d-8c32-c1e8348cb9b0
119115ba-3cd7-4c99-87f5-7cc415cd913d
1616286b-02b8-43e8-9e7e-50c487220f2a
e4eb6fe0-a81e-4a4a-9b96-6df1e75f027b

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)

24b9ea04-200c-11f1-a987-4cf95d479851
24b9ea68-200c-11f1-a987-4cf95d479851
24b9eac2-200c-11f1-a987-4cf95d479851
24b9eb1c-200c-11f1-a987-4cf95d479851
24b9eb80-200c-11f1-a987-4cf95d479851
24b9ebda-200c-11f1-a987-4cf95d479851
24b9ec3e-200c-11f1-a987-4cf95d479851
24b9ec8e-200c-11f1-a987-4cf95d479851
24b9ecf2-200c-11f1-a987-4cf95d479851
24b9ed4c-200c-11f1-a987-4cf95d479851
24b9eda6-200c-11f1-a987-4cf95d479851
24b9ee00-200c-11f1-a987-4cf95d479851
24b9ee5a-200c-11f1-a987-4cf95d479851
24b9eebe-200c-11f1-a987-4cf95d479851
24b9ef18-200c-11f1-a987-4cf95d479851

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)

be3a4e0f-4a00-8a04-87ea-5ce32bd83b97
03c94f0f-4a00-8a04-87ea-5ce32bd83b97
17c9500f-4a00-8a04-87ea-5ce32bd83b97
b064510f-4a00-8a04-87ea-5ce32bd83b97
037c520f-4a00-8a04-87ea-5ce32bd83b97
05b0530f-4a00-8a04-87ea-5ce32bd83b97
09b4540f-4a00-8a04-87ea-5ce32bd83b97
05b4550f-4a00-8a04-87ea-5ce32bd83b97
5d9f560f-4a00-8a04-87ea-5ce32bd83b97
2b2b570f-4a00-8a04-87ea-5ce32bd83b97
ad9f580f-4a00-8a04-87ea-5ce32bd83b97
cec9590f-4a00-8a04-87ea-5ce32bd83b97
bffc5a0f-4a00-8a04-87ea-5ce32bd83b97
a4df5b0f-4a00-8a04-87ea-5ce32bd83b97
f67f5c0f-4a00-8a04-87ea-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: