UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f8c39-ccf3-7171-be7a-815999d311f6
019f8c39-ccf3-732c-a711-918f4320cb5c
019f8c39-ccf3-7463-b24c-d3b26d5ed7b8
019f8c39-ccf3-7582-b00e-80beaaef2ddc
019f8c39-ccf3-7694-9522-cba71956e732
019f8c39-ccf3-77a2-b379-213efd865b0a
019f8c39-ccf3-78b5-9c4c-71b810b3ea6e
019f8c39-ccf3-79c7-b49c-bf0ba584672b
019f8c39-ccf3-7ada-8957-15a40df7c066
019f8c39-ccf3-7bec-8b4b-7cb76662f5bd
019f8c39-ccf3-7cfe-acdb-1ca0d45fa500
019f8c39-ccf3-7e11-aa40-e1241568cda3
019f8c39-ccf3-7f23-8097-03f68177386d
019f8c39-ccf4-7036-b0cb-5454668007fb
019f8c39-ccf4-7148-99ee-3edb31e47bbf

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)

1f18627a-5574-63d8-b45c-4cf95d479851
1f18627a-5574-657c-b45c-4cf95d479851
1f18627a-5574-6662-b45c-4cf95d479851
1f18627a-5574-672a-b45c-4cf95d479851
1f18627a-5574-67f2-b45c-4cf95d479851
1f18627a-5574-68ba-b45c-4cf95d479851
1f18627a-5574-6978-b45c-4cf95d479851
1f18627a-5574-6a36-b45c-4cf95d479851
1f18627a-5574-6af4-b45c-4cf95d479851
1f18627a-5574-6bb2-b45c-4cf95d479851
1f18627a-5574-6d10-b45c-4cf95d479851
1f18627a-5574-6de2-b45c-4cf95d479851
1f18627a-5574-6ea0-b45c-4cf95d479851
1f18627a-5574-6f5e-b45c-4cf95d479851
1f18627a-5575-6012-b45c-4cf95d479851

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)

a55750e4-8627-11f1-b45c-4cf95d479851
a5575148-8627-11f1-b45c-4cf95d479851
a55751a2-8627-11f1-b45c-4cf95d479851
a55751fc-8627-11f1-b45c-4cf95d479851
a5575260-8627-11f1-b45c-4cf95d479851
a55752ba-8627-11f1-b45c-4cf95d479851
a5575328-8627-11f1-b45c-4cf95d479851
a5575396-8627-11f1-b45c-4cf95d479851
a55753fa-8627-11f1-b45c-4cf95d479851
a5575468-8627-11f1-b45c-4cf95d479851
a55754cc-8627-11f1-b45c-4cf95d479851
a557553a-8627-11f1-b45c-4cf95d479851
a557559e-8627-11f1-b45c-4cf95d479851
a5575602-8627-11f1-b45c-4cf95d479851
a5575666-8627-11f1-b45c-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

1fc71a06-9405-8b0c-87ea-5ce32bd83b97
9d641b06-9405-8b0c-87ea-5ce32bd83b97
8c591c06-9405-8b0c-87ea-5ce32bd83b97
511f1d06-9405-8b0c-87ea-5ce32bd83b97
9c101e06-9405-8b0c-87ea-5ce32bd83b97
bac21f06-9405-8b0c-87ea-5ce32bd83b97
edb52006-9405-8b0c-87ea-5ce32bd83b97
1df52106-9405-8b0c-87ea-5ce32bd83b97
627c2206-9405-8b0c-87ea-5ce32bd83b97
fabc2306-9405-8b0c-87ea-5ce32bd83b97
65912406-9405-8b0c-87ea-5ce32bd83b97
e0ff2506-9405-8b0c-87ea-5ce32bd83b97
bb2f2606-9405-8b0c-87ea-5ce32bd83b97
900a2706-9405-8b0c-87ea-5ce32bd83b97
0f652806-9405-8b0c-87ea-5ce32bd83b97

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)

0f9cfcf9-7d01-42ad-b236-ac120dc3a212
9348a05d-e350-43f4-8966-9e22c8525338
cd6ad1c8-d6e4-4020-9f0c-6e24a9441fda
2c7727df-c597-484e-84c1-384d205bf81e
7fed8d7b-dcd1-4a05-8085-f31b0c380f74
31f44508-eda3-4aa8-bc69-8902672fc2f8
2159b652-c538-439e-8ebe-89d33f8c2c6c
704487d9-34e4-4c84-8691-ad6d37a4519e
77ba10e9-a069-4743-afdd-e0e9593b5b9e
4b99d208-a38e-45f9-a127-11bd0673c45c
c9a3f601-7415-417e-9659-4b5977759410
53493723-87f8-4f56-96a9-811bd7740d5c
3d04fe2b-cc47-44d0-be8f-b6b8d7f83625
14e05536-5e60-498e-9fb9-c2e95f50ff6b
4edbc110-4276-4df8-a6e3-5e2268ede83b

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: