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)

019abccb-9fe2-77d3-a489-6eb7114fd666
019abccb-9fe2-79bb-820d-058290cc52a6
019abccb-9fe2-7b03-afb3-db52b78261f5
019abccb-9fe2-7c25-8dec-1dc115009708
019abccb-9fe2-7d44-9a84-c9eaf9908a31
019abccb-9fe2-7e5b-9977-3dac936bcb86
019abccb-9fe2-7f71-aefe-b42a74aa0eb1
019abccb-9fe3-708c-b21c-3ed3d352c522
019abccb-9fe3-71a6-b468-172da2933bb5
019abccb-9fe3-72bd-a6fd-ad26e13c3242
019abccb-9fe3-73d8-a059-f3cfdbd0ade4
019abccb-9fe3-7561-bdf1-27c28969fdad
019abccb-9fe3-76b9-8070-387fa51f25cd
019abccb-9fe3-77dc-8503-5c03a21ecef1
019abccb-9fe3-78fa-b9fa-eaa643bddea7

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)

1f0ca40e-596e-6e4c-a038-4cf95d479851
1f0ca40e-596f-6040-a038-4cf95d479851
1f0ca40e-596f-6130-a038-4cf95d479851
1f0ca40e-596f-620c-a038-4cf95d479851
1f0ca40e-596f-62d4-a038-4cf95d479851
1f0ca40e-596f-639c-a038-4cf95d479851
1f0ca40e-596f-645a-a038-4cf95d479851
1f0ca40e-596f-6518-a038-4cf95d479851
1f0ca40e-596f-65e0-a038-4cf95d479851
1f0ca40e-596f-669e-a038-4cf95d479851
1f0ca40e-596f-67f2-a038-4cf95d479851
1f0ca40e-596f-68c4-a038-4cf95d479851
1f0ca40e-596f-6982-a038-4cf95d479851
1f0ca40e-596f-6a40-a038-4cf95d479851
1f0ca40e-596f-6afe-a038-4cf95d479851

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)

c2428102-f26c-406b-b9b3-22f7092461bc
60e77ba1-ea7c-4741-b508-2798a68a91aa
de8598f0-566d-4efc-8e2b-a19098aaf938
b8d4787a-bc1f-4889-85ad-3e025f6b3d1a
2e4f7722-99c8-40e2-abbc-f28b8c3ab121
37a11f3e-e719-4f77-917f-bb7c5565dd78
b8c7b0e8-9e85-4020-a44b-4dbfcc1913ba
bc854226-163f-417a-bebe-61ac79af90d4
3f13370f-89b9-4031-a3dc-1653a2c1c5fe
899f8d5f-8518-4b96-b7db-219a5cc23439
8a74bcfa-a859-424e-be23-b152e7877cdf
364e4d64-57e4-435f-89c1-44b2e27b4540
855671ac-5e07-4fec-98f6-c866431656b1
4eafd98a-0989-470f-8a4d-baf775826c72
1c4c55c8-d02d-42c6-a320-a568fddeffce

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)

e597003a-ca40-11f0-a038-4cf95d479851
e597009e-ca40-11f0-a038-4cf95d479851
e5970102-ca40-11f0-a038-4cf95d479851
e5970166-ca40-11f0-a038-4cf95d479851
e59701ca-ca40-11f0-a038-4cf95d479851
e5970224-ca40-11f0-a038-4cf95d479851
e5970292-ca40-11f0-a038-4cf95d479851
e597030a-ca40-11f0-a038-4cf95d479851
e597036e-ca40-11f0-a038-4cf95d479851
e59703d2-ca40-11f0-a038-4cf95d479851
e5970440-ca40-11f0-a038-4cf95d479851
e59704a4-ca40-11f0-a038-4cf95d479851
e5970508-ca40-11f0-a038-4cf95d479851
e5970562-ca40-11f0-a038-4cf95d479851
e59705c6-ca40-11f0-a038-4cf95d479851

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)

8fccb50c-e704-8914-87e9-5ce32bd83b97
9172b60c-e704-8914-87e9-5ce32bd83b97
ab42b70c-e704-8914-87e9-5ce32bd83b97
d0c6b80c-e704-8914-87e9-5ce32bd83b97
1742b90c-e704-8914-87e9-5ce32bd83b97
0e81ba0c-e704-8914-87e9-5ce32bd83b97
ff22bb0c-e704-8914-87e9-5ce32bd83b97
2cccbc0c-e704-8914-87e9-5ce32bd83b97
c6dbbd0c-e704-8914-87e9-5ce32bd83b97
9ba3be0c-e704-8914-87e9-5ce32bd83b97
377fbf0c-e704-8914-87e9-5ce32bd83b97
a7cbc00c-e704-8914-87e9-5ce32bd83b97
3a1ac10c-e704-8914-87e9-5ce32bd83b97
6017c20c-e704-8914-87e9-5ce32bd83b97
3786c40c-e704-8914-87e9-5ce32bd83b97

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

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: