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)

019c8977-122d-7d07-a608-8ead0cbc9be8
019c8977-122d-7e90-9b20-e7881ba6fcef
019c8977-122d-7fcf-b0ae-8414a206b8ee
019c8977-122e-70ea-89ba-de73a3d2b0ca
019c8977-122e-7205-9414-1f20e157016c
019c8977-122e-731b-b2f8-06db2aa33eb5
019c8977-122e-7436-9989-f680e92ce983
019c8977-122e-754c-88ad-5f8bca3e3d5b
019c8977-122e-765f-a04f-49e0be023169
019c8977-122e-7775-80ba-2ce36567077a
019c8977-122e-7890-b1cc-805200a03010
019c8977-122e-79a6-9410-cc2f44cfb22b
019c8977-122e-7abd-a2ad-e25f7da89090
019c8977-122e-7bd3-a017-a5007573cad9
019c8977-122e-7cea-b807-bb27bf1cc325

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)

1f1108bc-eb78-684e-97ce-4cf95d479851
1f1108bc-eb78-69d4-97ce-4cf95d479851
1f1108bc-eb78-6ac4-97ce-4cf95d479851
1f1108bc-eb78-6b8c-97ce-4cf95d479851
1f1108bc-eb78-6c54-97ce-4cf95d479851
1f1108bc-eb78-6dd0-97ce-4cf95d479851
1f1108bc-eb78-6e98-97ce-4cf95d479851
1f1108bc-eb78-6f60-97ce-4cf95d479851
1f1108bc-eb79-601e-97ce-4cf95d479851
1f1108bc-eb79-60e6-97ce-4cf95d479851
1f1108bc-eb79-6226-97ce-4cf95d479851
1f1108bc-eb79-62f8-97ce-4cf95d479851
1f1108bc-eb79-63c0-97ce-4cf95d479851
1f1108bc-eb79-647e-97ce-4cf95d479851
1f1108bc-eb79-653c-97ce-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)

ecab6a75-7cd0-480a-8590-faec7ccea180
ea0e2d6a-062b-4861-abd8-dbfef8221836
9e26bf07-367b-4672-aa05-f78d610af0cf
34fc75fa-a7ed-4d42-9974-7d4e45e22ff7
d126b7ec-616d-43f9-aff5-6f55c0c0863c
3f5f5bcd-785f-4acf-bbc8-09d8993d5cd7
04be10c0-e3c3-4201-9930-653db3938585
c04a0a0a-d946-4768-be21-d44aa4a0aa89
d67664a6-ba6c-4e3e-a6e2-1f0d125c9d4e
c37bc177-54b9-4087-b3d7-f8c5a84e1c30
195ee0a0-d365-4581-aa90-605c8198c298
b50aaf46-bcc2-4886-a26e-fea23a3a2859
bbe3960b-c4f8-4ae0-a43d-f1d3637b661c
422b1531-273f-4e9d-8133-349928455105
5037cbd0-5678-4952-a6d0-b147e8e2079e

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)

ceb79a64-108b-11f1-97ce-4cf95d479851
ceb79ac8-108b-11f1-97ce-4cf95d479851
ceb79b2c-108b-11f1-97ce-4cf95d479851
ceb79b86-108b-11f1-97ce-4cf95d479851
ceb79bea-108b-11f1-97ce-4cf95d479851
ceb79c4e-108b-11f1-97ce-4cf95d479851
ceb79ca8-108b-11f1-97ce-4cf95d479851
ceb79d02-108b-11f1-97ce-4cf95d479851
ceb79d66-108b-11f1-97ce-4cf95d479851
ceb79dd4-108b-11f1-97ce-4cf95d479851
ceb79e2e-108b-11f1-97ce-4cf95d479851
ceb79e92-108b-11f1-97ce-4cf95d479851
ceb79eec-108b-11f1-97ce-4cf95d479851
ceb79f5a-108b-11f1-97ce-4cf95d479851
ceb79fb4-108b-11f1-97ce-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)

d474fb2f-d301-8603-87ea-5ce32bd83b97
b77dfc2f-d301-8603-87ea-5ce32bd83b97
ae98fd2f-d301-8603-87ea-5ce32bd83b97
a2c1fe2f-d301-8603-87ea-5ce32bd83b97
6a00ff2f-d301-8603-87ea-5ce32bd83b97
92b90130-d301-8603-87ea-5ce32bd83b97
ad6b0230-d301-8603-87ea-5ce32bd83b97
2b4f0330-d301-8603-87ea-5ce32bd83b97
38e10430-d301-8603-87ea-5ce32bd83b97
ccb90530-d301-8603-87ea-5ce32bd83b97
38e60630-d301-8603-87ea-5ce32bd83b97
d5600730-d301-8603-87ea-5ce32bd83b97
934b0830-d301-8603-87ea-5ce32bd83b97
d0ff0930-d301-8603-87ea-5ce32bd83b97
abee0a30-d301-8603-87ea-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: