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)

019cc91b-216b-75d8-8a7e-7b34422db5aa
019cc91b-216b-7754-a382-13014345ada2
019cc91b-216b-7898-b86b-dcf1b7f278f1
019cc91b-216b-79bf-b34d-21f6df8fcad0
019cc91b-216b-7ada-9025-22414b722d76
019cc91b-216b-7bf4-9364-b0083d2b173d
019cc91b-216b-7d13-8e39-089c4643e5b4
019cc91b-216b-7e5f-a54d-7e44e209f705
019cc91b-216b-7f82-bbd3-031595def3b9
019cc91b-216c-7150-b080-ffaa0a6dd1d7
019cc91b-216c-727b-8d8b-654eb90f7279
019cc91b-216c-7396-8bed-5b0fd817b176
019cc91b-216c-74b1-854f-608bb627c309
019cc91b-216c-75c7-9dee-e375e6759a70
019cc91b-216c-76e2-b03e-15287cae2023

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)

1f11a41c-74ad-6fa6-9f9c-4cf95d479851
1f11a41c-74ae-6136-9f9c-4cf95d479851
1f11a41c-74ae-621c-9f9c-4cf95d479851
1f11a41c-74ae-62e4-9f9c-4cf95d479851
1f11a41c-74ae-63ac-9f9c-4cf95d479851
1f11a41c-74ae-646a-9f9c-4cf95d479851
1f11a41c-74ae-6532-9f9c-4cf95d479851
1f11a41c-74ae-65f0-9f9c-4cf95d479851
1f11a41c-74ae-66b8-9f9c-4cf95d479851
1f11a41c-74ae-6780-9f9c-4cf95d479851
1f11a41c-74ae-68de-9f9c-4cf95d479851
1f11a41c-74ae-69a6-9f9c-4cf95d479851
1f11a41c-74ae-6a64-9f9c-4cf95d479851
1f11a41c-74ae-6b2c-9f9c-4cf95d479851
1f11a41c-74ae-6bea-9f9c-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)

8b29b4a4-91a3-4ad0-98b6-d9bcf9a7a5f8
1458887a-6317-4d4e-b84f-beedf5ddb81b
1f01fea5-176e-4617-ad60-da9c42afe736
9be67d39-724e-4b85-a898-087639aa15fb
cd800720-73b0-4491-8167-4803fba3f025
b8da7c0a-48ae-4fac-a4d7-a2f6d88bbbaa
0299420f-acde-4027-8f88-3dfb462a494e
2d6eb085-ea09-4935-8cc2-a7a3d1c329a5
b6248210-6319-421a-b42c-be1af78cd16e
6ba520a7-f236-40b5-9886-43760ac9f60d
ae0edb90-63c9-4b88-8fa7-1126a9b6bb51
6b0df2e5-b995-4fd5-9714-93d2e5815721
c7646bc6-97e4-4779-ba78-bb57c2bbd7dc
53d4f8c8-792b-4a6c-971b-d1c5e99a860e
9fdac8f2-bfbd-429d-b8ea-8e98b062e3af

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)

c74af310-1a41-11f1-9f9c-4cf95d479851
c74af37e-1a41-11f1-9f9c-4cf95d479851
c74af3e2-1a41-11f1-9f9c-4cf95d479851
c74af446-1a41-11f1-9f9c-4cf95d479851
c74af4aa-1a41-11f1-9f9c-4cf95d479851
c74af50e-1a41-11f1-9f9c-4cf95d479851
c74af874-1a41-11f1-9f9c-4cf95d479851
c74af8f6-1a41-11f1-9f9c-4cf95d479851
c74af95a-1a41-11f1-9f9c-4cf95d479851
c74af9be-1a41-11f1-9f9c-4cf95d479851
c74afa22-1a41-11f1-9f9c-4cf95d479851
c74afa86-1a41-11f1-9f9c-4cf95d479851
c74afae0-1a41-11f1-9f9c-4cf95d479851
c74afb44-1a41-11f1-9f9c-4cf95d479851
c74afba8-1a41-11f1-9f9c-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)

8bc06504-d703-8204-87ea-5ce32bd83b97
55e26604-d703-8204-87ea-5ce32bd83b97
92bf6704-d703-8204-87ea-5ce32bd83b97
10166804-d703-8204-87ea-5ce32bd83b97
d0e16904-d703-8204-87ea-5ce32bd83b97
33c56a04-d703-8204-87ea-5ce32bd83b97
fe346b04-d703-8204-87ea-5ce32bd83b97
01466c04-d703-8204-87ea-5ce32bd83b97
d4166e04-d703-8204-87ea-5ce32bd83b97
6fd06f04-d703-8204-87ea-5ce32bd83b97
78947004-d703-8204-87ea-5ce32bd83b97
c0a87104-d703-8204-87ea-5ce32bd83b97
5b237204-d703-8204-87ea-5ce32bd83b97
f2407304-d703-8204-87ea-5ce32bd83b97
52e57404-d703-8204-87ea-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: