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)

01a107f6-da52-7cc9-8720-b0013be9e811
01a107f6-da52-7e4a-96d8-7670d7289ab4
01a107f6-da52-7f82-866f-a41f7f579194
01a107f6-da53-709c-927f-8e3edbacae15
01a107f6-da53-71b3-be64-ad6efffbb240
01a107f6-da53-72c9-a19e-4bffc15144cc
01a107f6-da53-73dc-971a-f5b465bc9f22
01a107f6-da53-74ee-93d1-3fa7121a8a29
01a107f6-da53-7605-833b-64f286503f4e
01a107f6-da53-771b-a317-07027d4ad666
01a107f6-da53-7832-8c4f-896aa04024c6
01a107f6-da53-7944-a820-2c5b2acb500e
01a107f6-da53-7a5b-b23b-684e1f6ec9b7
01a107f6-da53-7b6d-91e9-ac6dfedfcdb6
01a107f6-da53-7c7f-8302-ccba7d02aa07

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)

1f1c0192-e31a-6ca4-b5ec-4cf95d479851
1f1c0192-e31a-6e3e-b5ec-4cf95d479851
1f1c0192-e31a-6f24-b5ec-4cf95d479851
1f1c0192-e31a-6fec-b5ec-4cf95d479851
1f1c0192-e31b-60aa-b5ec-4cf95d479851
1f1c0192-e31b-6172-b5ec-4cf95d479851
1f1c0192-e31b-6230-b5ec-4cf95d479851
1f1c0192-e31b-62e4-b5ec-4cf95d479851
1f1c0192-e31b-63ac-b5ec-4cf95d479851
1f1c0192-e31b-6460-b5ec-4cf95d479851
1f1c0192-e31b-65aa-b5ec-4cf95d479851
1f1c0192-e31b-6672-b5ec-4cf95d479851
1f1c0192-e31b-673a-b5ec-4cf95d479851
1f1c0192-e31b-67ee-b5ec-4cf95d479851
1f1c0192-e31b-68ac-b5ec-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)

2e31b97e-c019-11f1-b5ec-4cf95d479851
2e31b9e2-c019-11f1-b5ec-4cf95d479851
2e31ba46-c019-11f1-b5ec-4cf95d479851
2e31baaa-c019-11f1-b5ec-4cf95d479851
2e31bb04-c019-11f1-b5ec-4cf95d479851
2e31bb5e-c019-11f1-b5ec-4cf95d479851
2e31bbc2-c019-11f1-b5ec-4cf95d479851
2e31bc26-c019-11f1-b5ec-4cf95d479851
2e31bc8a-c019-11f1-b5ec-4cf95d479851
2e31bce4-c019-11f1-b5ec-4cf95d479851
2e31bd48-c019-11f1-b5ec-4cf95d479851
2e31bdac-c019-11f1-b5ec-4cf95d479851
2e31be10-c019-11f1-b5ec-4cf95d479851
2e31be74-c019-11f1-b5ec-4cf95d479851
2e31bed8-c019-11f1-b5ec-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)

e39fb128-1a04-8511-87ea-5ce32bd83b97
0b84b228-1a04-8511-87ea-5ce32bd83b97
99c1b328-1a04-8511-87ea-5ce32bd83b97
26f5b428-1a04-8511-87ea-5ce32bd83b97
6454b528-1a04-8511-87ea-5ce32bd83b97
e08bb628-1a04-8511-87ea-5ce32bd83b97
97d6b728-1a04-8511-87ea-5ce32bd83b97
9b9cb828-1a04-8511-87ea-5ce32bd83b97
78b6b928-1a04-8511-87ea-5ce32bd83b97
1491ba28-1a04-8511-87ea-5ce32bd83b97
aadfbb28-1a04-8511-87ea-5ce32bd83b97
7e17bc28-1a04-8511-87ea-5ce32bd83b97
49f4bd28-1a04-8511-87ea-5ce32bd83b97
7e7ebe28-1a04-8511-87ea-5ce32bd83b97
65d6bf28-1a04-8511-87ea-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)

601bc40f-e471-48f5-a37a-a6b49e438fb5
9cf2f428-38ab-4f3f-8117-060a97519529
7a862024-8229-47c3-a33a-dbc4b0c4894b
9e9fb930-a6fb-4fac-aba4-29c08f000828
61a55ba5-b504-484e-8dd6-e628acc47705
d44395bf-7265-4595-8b1d-67f922ca3dc4
00335d8d-9fbb-4e5a-bfe3-1f18ede39166
67adc138-1cb8-4398-b8f1-94cc4a7412b6
75ad7fe5-08d8-41f1-95f5-30971ec81734
c7cd6210-49a4-48ee-86ab-bb4a501bc874
e81dd591-8477-40db-82b5-1120f04f126d
6d20b0ec-be39-4390-86d9-0719f5c6b754
203eb5b3-5ba5-41d9-97c5-d9fea3f9c58f
57b80491-0f55-43c9-8447-a3e8c7471306
ae7bd2d6-b779-410c-b5ea-a108653bab26

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: