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)

019c560a-bfb4-7cf6-aa3e-2d5ade576d27
019c560a-bfb4-7e98-9f34-68ce085c9e71
019c560a-bfb4-7fd8-98c6-57f4fcb9054a
019c560a-bfb5-70fe-aee3-0dbfc79e9263
019c560a-bfb5-7221-a908-90c58b04d4d4
019c560a-bfb5-733c-b6aa-43e5f55a938b
019c560a-bfb5-7457-8c65-21f59e6e557c
019c560a-bfb5-7571-a78b-4982dbbf7f48
019c560a-bfb5-768c-b211-39cc5dbe814c
019c560a-bfb5-77aa-b3bc-ab08a65f6dc5
019c560a-bfb5-78c9-89fc-6c36bc647377
019c560a-bfb5-79e0-874d-ea3e183aac5d
019c560a-bfb5-7afa-bec2-cf83530ae568
019c560a-bfb5-7c19-a661-a14e3fcc03de
019c560a-bfb5-7d34-9201-6c2cbb4afa14

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)

1f108b31-761f-62c2-9a12-4cf95d479851
1f108b31-761f-6466-9a12-4cf95d479851
1f108b31-761f-654c-9a12-4cf95d479851
1f108b31-761f-661e-9a12-4cf95d479851
1f108b31-761f-66e6-9a12-4cf95d479851
1f108b31-761f-67ae-9a12-4cf95d479851
1f108b31-761f-686c-9a12-4cf95d479851
1f108b31-761f-692a-9a12-4cf95d479851
1f108b31-761f-69f2-9a12-4cf95d479851
1f108b31-761f-6ab0-9a12-4cf95d479851
1f108b31-761f-6c0e-9a12-4cf95d479851
1f108b31-761f-6cd6-9a12-4cf95d479851
1f108b31-761f-6d94-9a12-4cf95d479851
1f108b31-761f-6e52-9a12-4cf95d479851
1f108b31-761f-6f1a-9a12-4cf95d479851

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)

1971fd01-e5e4-432d-b3c6-5511c1dc7652
f2e32348-ef89-42f2-ba14-fa2fca873c34
167f962a-98ec-407a-8a90-caf4ce232c5d
172bf308-b3c0-4a83-b9d8-c9148e493d6e
88c28a52-94e0-494b-bc0b-8d1aad1c60e7
12aac97b-0ece-4d62-ba3b-bd231dc8d5be
908d4221-dcf0-4bde-93d7-7dd22ca67af3
cde9d027-b38d-44a8-abd0-e46146dc3ce6
e23c5ee5-e2c5-4a12-aef2-5f4d8a4da11c
5628b6cc-1f1c-4f6e-ae94-a6a4f97d12f6
cf764228-28af-4def-a07e-425b28d28f90
e79e9842-d04e-44b0-9f35-b2428976a21d
ec3e9a23-d85a-4385-8599-7bcccdec3c0e
9aa652e1-458e-44b8-992f-9d1bebbe2187
0d57d9bf-081d-43d0-802a-a640908463fb

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)

1762046a-08b3-11f1-9a12-4cf95d479851
176204c4-08b3-11f1-9a12-4cf95d479851
17620528-08b3-11f1-9a12-4cf95d479851
17620582-08b3-11f1-9a12-4cf95d479851
176205e6-08b3-11f1-9a12-4cf95d479851
17620640-08b3-11f1-9a12-4cf95d479851
176206a4-08b3-11f1-9a12-4cf95d479851
176206fe-08b3-11f1-9a12-4cf95d479851
17620762-08b3-11f1-9a12-4cf95d479851
176207c6-08b3-11f1-9a12-4cf95d479851
17620820-08b3-11f1-9a12-4cf95d479851
17620884-08b3-11f1-9a12-4cf95d479851
176208f2-08b3-11f1-9a12-4cf95d479851
17620956-08b3-11f1-9a12-4cf95d479851
176209ba-08b3-11f1-9a12-4cf95d479851

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)

27b8f732-e801-8c02-87ea-5ce32bd83b97
d4a2f832-e801-8c02-87ea-5ce32bd83b97
e1ecf932-e801-8c02-87ea-5ce32bd83b97
1e9bfa32-e801-8c02-87ea-5ce32bd83b97
7e35fb32-e801-8c02-87ea-5ce32bd83b97
c21dfc32-e801-8c02-87ea-5ce32bd83b97
b96bfd32-e801-8c02-87ea-5ce32bd83b97
44adfe32-e801-8c02-87ea-5ce32bd83b97
a19bff32-e801-8c02-87ea-5ce32bd83b97
bf390133-e801-8c02-87ea-5ce32bd83b97
ea840233-e801-8c02-87ea-5ce32bd83b97
c2de0333-e801-8c02-87ea-5ce32bd83b97
f3ee0433-e801-8c02-87ea-5ce32bd83b97
72bd0533-e801-8c02-87ea-5ce32bd83b97
08d10633-e801-8c02-87ea-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: