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)

01a04507-c2c3-7d1f-bb2d-48cd866fd89c
01a04507-c2c3-7eb1-a184-66289b01ba75
01a04507-c2c3-7fe4-b370-44845a4386bc
01a04507-c2c4-70fe-94d5-3b00eee6f4ab
01a04507-c2c4-7215-9b40-a68022a040c3
01a04507-c2c4-7327-b1d7-ec44ba3fb486
01a04507-c2c4-743e-a073-1731fcc81292
01a04507-c2c4-7554-a7ea-d2bd8a309b8d
01a04507-c2c4-7667-a627-af963d92f8fb
01a04507-c2c4-7779-929e-6b4b7935af21
01a04507-c2c4-788c-9fed-2b5743673da6
01a04507-c2c4-799e-9c54-d1c0771a255f
01a04507-c2c4-7ab1-997e-1a9a3ec4d59b
01a04507-c2c4-7bc3-8c66-9dfb02be5b56
01a04507-c2c4-7ce2-ba7b-800a4e445401

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)

1f1a25a9-2a96-6d16-be5b-4cf95d479851
1f1a25a9-2a96-6eb0-be5b-4cf95d479851
1f1a25a9-2a96-6f96-be5b-4cf95d479851
1f1a25a9-2a97-605e-be5b-4cf95d479851
1f1a25a9-2a97-6126-be5b-4cf95d479851
1f1a25a9-2a97-61e4-be5b-4cf95d479851
1f1a25a9-2a97-62a2-be5b-4cf95d479851
1f1a25a9-2a97-6356-be5b-4cf95d479851
1f1a25a9-2a97-640a-be5b-4cf95d479851
1f1a25a9-2a97-64c8-be5b-4cf95d479851
1f1a25a9-2a97-65fe-be5b-4cf95d479851
1f1a25a9-2a97-66d0-be5b-4cf95d479851
1f1a25a9-2a97-6784-be5b-4cf95d479851
1f1a25a9-2a97-68b0-be5b-4cf95d479851
1f1a25a9-2a97-69a0-be5b-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)

92a97a72-a25a-11f1-be5b-4cf95d479851
92a97ad6-a25a-11f1-be5b-4cf95d479851
92a97b3a-a25a-11f1-be5b-4cf95d479851
92a97b94-a25a-11f1-be5b-4cf95d479851
92a97bf8-a25a-11f1-be5b-4cf95d479851
92a97c5c-a25a-11f1-be5b-4cf95d479851
92a97cc0-a25a-11f1-be5b-4cf95d479851
92a97d2e-a25a-11f1-be5b-4cf95d479851
92a97d9c-a25a-11f1-be5b-4cf95d479851
92a97df6-a25a-11f1-be5b-4cf95d479851
92a97e64-a25a-11f1-be5b-4cf95d479851
92a97ec8-a25a-11f1-be5b-4cf95d479851
92a97f2c-a25a-11f1-be5b-4cf95d479851
92a97f90-a25a-11f1-be5b-4cf95d479851
92a97ff4-a25a-11f1-be5b-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)

b556a70b-ef04-8f0e-87ea-5ce32bd83b97
b4efa80b-ef04-8f0e-87ea-5ce32bd83b97
e9baa90b-ef04-8f0e-87ea-5ce32bd83b97
87c4aa0b-ef04-8f0e-87ea-5ce32bd83b97
892bab0b-ef04-8f0e-87ea-5ce32bd83b97
c3c7ac0b-ef04-8f0e-87ea-5ce32bd83b97
70d7ad0b-ef04-8f0e-87ea-5ce32bd83b97
8a99ae0b-ef04-8f0e-87ea-5ce32bd83b97
dc2daf0b-ef04-8f0e-87ea-5ce32bd83b97
0f45b00b-ef04-8f0e-87ea-5ce32bd83b97
7c1db10b-ef04-8f0e-87ea-5ce32bd83b97
c7b9b20b-ef04-8f0e-87ea-5ce32bd83b97
4a86b30b-ef04-8f0e-87ea-5ce32bd83b97
2112b40b-ef04-8f0e-87ea-5ce32bd83b97
6089b50b-ef04-8f0e-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)

c7587858-8e30-4943-b645-f4b81ecd3e9d
582b430a-08bc-40f2-a4a0-a24bd27548a7
8d2981ea-f9c1-438c-a55a-986b4dcd2746
36d3861b-d53e-4dfc-be6f-8a058814b44c
9c22c328-4fb5-4c84-9e33-c64782976f20
c90c683c-9ee7-4d24-966e-78c60be1638d
0faefcfa-0f9a-47a2-a8e2-7e346b82d699
74488432-4008-4a20-b1d3-e455a5627186
79de2124-8639-4cdc-8a6c-7e30b8691e36
bc5355af-ec97-4897-97e8-09c7c77bb318
e7533590-b17a-4581-b389-e9d57f564cac
958a3350-4680-4252-aa15-ecc13f10f447
4b563581-690c-4b2d-a8da-515fe34fcd50
42fb0380-394d-426d-a18e-65d7b2cdcdde
d82577ca-598e-485b-ae4c-836ab74f34d3

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: