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)

019e610b-bb90-7ffc-a218-6a1d30290f6d
019e610b-bb91-7186-87ff-4ff04bd8ca9e
019e610b-bb91-72c9-8701-8bdb5266f5a6
019e610b-bb91-73e8-8c79-af5c116e012b
019e610b-bb91-74fe-aba2-126ecaee11b6
019e610b-bb91-7615-9e37-35ee82cc4bf6
019e610b-bb91-772c-9a29-c70f30b3afc4
019e610b-bb91-7842-a040-500ee5e3fb6c
019e610b-bb91-7959-80a7-1227301753b6
019e610b-bb91-7a6f-9edf-9cbd13af292e
019e610b-bb91-7b86-b858-f6c304334181
019e610b-bb91-7c9c-bf91-8010a8f4a0f3
019e610b-bb91-7daf-a62c-b8bd73350c05
019e610b-bb91-7ec5-9a16-31f926d2d1ce
019e610b-bb91-7fd8-b92c-34623ef889eb

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)

1f15880e-dd03-6ab8-be27-4cf95d479851
1f15880e-dd03-6c8e-be27-4cf95d479851
1f15880e-dd03-6d7e-be27-4cf95d479851
1f15880e-dd03-6e5a-be27-4cf95d479851
1f15880e-dd03-6f22-be27-4cf95d479851
1f15880e-dd03-6ff4-be27-4cf95d479851
1f15880e-dd04-60bc-be27-4cf95d479851
1f15880e-dd04-6184-be27-4cf95d479851
1f15880e-dd04-624c-be27-4cf95d479851
1f15880e-dd04-6314-be27-4cf95d479851
1f15880e-dd04-647c-be27-4cf95d479851
1f15880e-dd04-6558-be27-4cf95d479851
1f15880e-dd04-6620-be27-4cf95d479851
1f15880e-dd04-66e8-be27-4cf95d479851
1f15880e-dd04-67b0-be27-4cf95d479851

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)

edd0488c-5880-11f1-be27-4cf95d479851
edd048fa-5880-11f1-be27-4cf95d479851
edd04968-5880-11f1-be27-4cf95d479851
edd049cc-5880-11f1-be27-4cf95d479851
edd04a94-5880-11f1-be27-4cf95d479851
edd04b02-5880-11f1-be27-4cf95d479851
edd04b66-5880-11f1-be27-4cf95d479851
edd04bca-5880-11f1-be27-4cf95d479851
edd04c24-5880-11f1-be27-4cf95d479851
edd04c88-5880-11f1-be27-4cf95d479851
edd04ce2-5880-11f1-be27-4cf95d479851
edd04d46-5880-11f1-be27-4cf95d479851
edd04da0-5880-11f1-be27-4cf95d479851
edd04e04-5880-11f1-be27-4cf95d479851
edd04e68-5880-11f1-be27-4cf95d479851

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)

a44e6913-0b05-8109-87ea-5ce32bd83b97
549d6a13-0b05-8109-87ea-5ce32bd83b97
84796b13-0b05-8109-87ea-5ce32bd83b97
73366c13-0b05-8109-87ea-5ce32bd83b97
8d6e6d13-0b05-8109-87ea-5ce32bd83b97
19006e13-0b05-8109-87ea-5ce32bd83b97
63e76f13-0b05-8109-87ea-5ce32bd83b97
9ec57013-0b05-8109-87ea-5ce32bd83b97
e5c57113-0b05-8109-87ea-5ce32bd83b97
32a47213-0b05-8109-87ea-5ce32bd83b97
96e27313-0b05-8109-87ea-5ce32bd83b97
f78b7413-0b05-8109-87ea-5ce32bd83b97
3fa27513-0b05-8109-87ea-5ce32bd83b97
a01c7613-0b05-8109-87ea-5ce32bd83b97
62e57713-0b05-8109-87ea-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)

1bad169a-4927-4c49-a019-7d96e8e6eb6a
9d2f4e72-d319-4679-8300-2b2f3592bfa3
b5ee62b8-40fe-4e51-98a1-fde28516ee3d
23072d23-ea9c-4c8d-904e-9032c79e23bc
fdf040ce-05a9-4556-b4c0-41a4c4c90800
dbe3457c-9250-4463-97a8-0861e3ea107a
5806b647-dae1-416e-999c-4cb1bcd7d544
76f2da61-8cd1-4e15-8da4-be6ebc900d37
87a0c0eb-b643-44b0-9c20-2fe93f9a76c6
8a190f95-1551-4be6-9865-fd7bbb7a6df7
4f577c08-0486-44fd-9cd1-9a172946c8a2
d5157215-9840-4a49-abec-f0d6bd86835c
1330a10f-4feb-4ea9-90cd-64f878a2a255
ae1f87cb-0f0a-47c6-81b7-eff0163488a8
c95b74f5-ce0f-417d-b8ca-107ed543fd7d

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: