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)

019bf451-11ea-796d-ad4d-0e439533fdb7
019bf451-11ea-7afe-822d-d9e8c2a8c82a
019bf451-11ea-7c3a-b7d1-3fab2c48b062
019bf451-11ea-7d59-8807-bf10716026e3
019bf451-11ea-7e73-8e5c-4afca3225eef
019bf451-11ea-7f8a-a528-d740a2f5f611
019bf451-11eb-70a4-a881-3a200cef8810
019bf451-11eb-71bb-8f9e-1a32f5147cac
019bf451-11eb-72d5-a305-11898594a435
019bf451-11eb-73ec-9c01-389a1b23d8b2
019bf451-11eb-7503-856a-df68352bfb99
019bf451-11eb-7619-a24e-3732d15700a9
019bf451-11eb-7734-9cad-9d4bd4aa07f5
019bf451-11eb-784a-8684-c55c8224dd0d
019bf451-11eb-7969-8160-412400519de7

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)

1f0f9c9b-24d4-6686-b643-4cf95d479851
1f0f9c9b-24d4-682a-b643-4cf95d479851
1f0f9c9b-24d4-6910-b643-4cf95d479851
1f0f9c9b-24d4-69d8-b643-4cf95d479851
1f0f9c9b-24d4-6aa0-b643-4cf95d479851
1f0f9c9b-24d4-6b68-b643-4cf95d479851
1f0f9c9b-24d4-6c26-b643-4cf95d479851
1f0f9c9b-24d4-6cee-b643-4cf95d479851
1f0f9c9b-24d4-6dac-b643-4cf95d479851
1f0f9c9b-24d4-6e6a-b643-4cf95d479851
1f0f9c9b-24d4-6faa-b643-4cf95d479851
1f0f9c9b-24d5-607c-b643-4cf95d479851
1f0f9c9b-24d5-613a-b643-4cf95d479851
1f0f9c9b-24d5-61f8-b643-4cf95d479851
1f0f9c9b-24d5-62c0-b643-4cf95d479851

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)

5af722ff-8595-42fe-8dcb-c4ee0b868011
7d5f0475-d367-484e-bc5d-4b0b7717bc1b
b2c0bfa8-73ba-4738-aeaa-9be0a2fc10fe
5739a700-4fa0-4418-b5eb-604e97746a4a
d8db95fd-0d4a-49ce-8f45-705e7822aacb
0c403dd3-84b5-4b32-9bf9-45787dd1896d
0f93ee59-4aeb-450b-9bfe-c0118158a666
f59ba882-ebc7-462f-bb54-4eb05fdba794
39a4f74f-0f75-40bb-aace-6c5ed9ab3026
26983d15-3d43-43a3-866f-4982d5bc1fc8
46cb6a1e-836d-4a3c-a328-4e4c07d116b3
45682d22-4291-4030-b6f8-2613ab12f83a
6c64c8e3-c421-4fa2-b079-db504f71401e
29a29dc6-a4c3-416e-a335-2a9133ae0b8e
937a7419-2e15-4932-9129-a2e20be4cc73

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)

b24d57ca-f9c9-11f0-b643-4cf95d479851
b24d5838-f9c9-11f0-b643-4cf95d479851
b24d5892-f9c9-11f0-b643-4cf95d479851
b24d58f6-f9c9-11f0-b643-4cf95d479851
b24d5950-f9c9-11f0-b643-4cf95d479851
b24d59aa-f9c9-11f0-b643-4cf95d479851
b24d5a0e-f9c9-11f0-b643-4cf95d479851
b24d5a68-f9c9-11f0-b643-4cf95d479851
b24d5acc-f9c9-11f0-b643-4cf95d479851
b24d5b26-f9c9-11f0-b643-4cf95d479851
b24d5b8a-f9c9-11f0-b643-4cf95d479851
b24d5be4-f9c9-11f0-b643-4cf95d479851
b24d5c3e-f9c9-11f0-b643-4cf95d479851
b24d5c98-f9c9-11f0-b643-4cf95d479851
b24d5cfc-f9c9-11f0-b643-4cf95d479851

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)

b2225d34-0a02-8901-87ea-5ce32bd83b97
826d5e34-0a02-8901-87ea-5ce32bd83b97
3f4f5f34-0a02-8901-87ea-5ce32bd83b97
0a7c6034-0a02-8901-87ea-5ce32bd83b97
471f6134-0a02-8901-87ea-5ce32bd83b97
e93f6234-0a02-8901-87ea-5ce32bd83b97
17386334-0a02-8901-87ea-5ce32bd83b97
777a6434-0a02-8901-87ea-5ce32bd83b97
3e3d6534-0a02-8901-87ea-5ce32bd83b97
cb166634-0a02-8901-87ea-5ce32bd83b97
97656734-0a02-8901-87ea-5ce32bd83b97
dbfd6834-0a02-8901-87ea-5ce32bd83b97
d2fc6934-0a02-8901-87ea-5ce32bd83b97
41bd6a34-0a02-8901-87ea-5ce32bd83b97
bcb96b34-0a02-8901-87ea-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: