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)

01a104ed-03a7-7e42-aef9-49a4f091eba3
01a104ed-03a7-7fe4-ad5e-0d5848e39cea
01a104ed-03a8-711f-9a01-93cd4aee29bc
01a104ed-03a8-723e-b144-612e862c4bed
01a104ed-03a8-7354-bcdd-b6044d1a18c2
01a104ed-03a8-746b-8f26-a22c57f03d6d
01a104ed-03a8-7582-a9f4-051e3e9683ee
01a104ed-03a8-7698-8597-5c64ffe157b6
01a104ed-03a8-77af-9de1-07bf11c58c79
01a104ed-03a8-78c1-8ce7-96d09a386441
01a104ed-03a8-79d8-a83f-3f342f89c50f
01a104ed-03a8-7aee-9aeb-5e7d8c2ca777
01a104ed-03a8-7c00-9922-73ed4382b65c
01a104ed-03a8-7d17-8069-f621776d35fc
01a104ed-03a8-7e2e-a080-4a9cd01795a4

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)

1f1bfa27-de03-692c-8351-4cf95d479851
1f1bfa27-de03-6ada-8351-4cf95d479851
1f1bfa27-de03-6bc0-8351-4cf95d479851
1f1bfa27-de03-6c88-8351-4cf95d479851
1f1bfa27-de03-6d50-8351-4cf95d479851
1f1bfa27-de03-6e18-8351-4cf95d479851
1f1bfa27-de03-6ed6-8351-4cf95d479851
1f1bfa27-de03-6f9e-8351-4cf95d479851
1f1bfa27-de04-605c-8351-4cf95d479851
1f1bfa27-de04-611a-8351-4cf95d479851
1f1bfa27-de04-62b4-8351-4cf95d479851
1f1bfa27-de04-63c2-8351-4cf95d479851
1f1bfa27-de04-648a-8351-4cf95d479851
1f1bfa27-de04-6548-8351-4cf95d479851
1f1bfa27-de04-6606-8351-4cf95d479851

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)

7de046d8-bfa2-11f1-8351-4cf95d479851
7de0473c-bfa2-11f1-8351-4cf95d479851
7de047a0-bfa2-11f1-8351-4cf95d479851
7de04804-bfa2-11f1-8351-4cf95d479851
7de0485e-bfa2-11f1-8351-4cf95d479851
7de048c2-bfa2-11f1-8351-4cf95d479851
7de0491c-bfa2-11f1-8351-4cf95d479851
7de04976-bfa2-11f1-8351-4cf95d479851
7de049da-bfa2-11f1-8351-4cf95d479851
7de04a34-bfa2-11f1-8351-4cf95d479851
7de04a98-bfa2-11f1-8351-4cf95d479851
7de04afc-bfa2-11f1-8351-4cf95d479851
7de04b56-bfa2-11f1-8351-4cf95d479851
7de04bba-bfa2-11f1-8351-4cf95d479851
7de04c1e-bfa2-11f1-8351-4cf95d479851

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)

04224404-c900-8511-87ea-5ce32bd83b97
edd14504-c900-8511-87ea-5ce32bd83b97
cdcf4604-c900-8511-87ea-5ce32bd83b97
417d4704-c900-8511-87ea-5ce32bd83b97
358e4804-c900-8511-87ea-5ce32bd83b97
d6344904-c900-8511-87ea-5ce32bd83b97
e8b14a04-c900-8511-87ea-5ce32bd83b97
022f4b04-c900-8511-87ea-5ce32bd83b97
e89e4c04-c900-8511-87ea-5ce32bd83b97
48844d04-c900-8511-87ea-5ce32bd83b97
c66e4e04-c900-8511-87ea-5ce32bd83b97
432f4f04-c900-8511-87ea-5ce32bd83b97
908f5004-c900-8511-87ea-5ce32bd83b97
77e75104-c900-8511-87ea-5ce32bd83b97
24c45204-c900-8511-87ea-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)

34fa3ab6-bc4a-4f52-870f-7f829afcf71b
cea50449-087b-4e6f-869b-5756106f8bda
b6b5e23d-4c9d-49d1-b43d-0640a53fd0fe
2ac3ed90-b288-474e-8223-93dc510e358d
31a72468-0b20-4b7e-9d39-7fe323f73bce
1350c830-83cb-4809-bf33-eb93a6752796
6977a053-6963-41c4-81c7-3f5a2db193fa
afbadf29-0de2-4c45-9c8a-5ffe6585e521
e913fc08-7192-4b8d-b11a-25e8d7f0d063
f1e9ac79-5706-417a-985c-2df538978fe0
0027bbc8-2f41-4f30-8a45-a742ef1ff517
87ff5326-915b-4ae9-ac4e-b9f7113e644a
8307257b-0699-4080-ac02-74a9d442956c
c4f8198e-7990-41da-8e38-5bd4ffd31efc
6d6babca-9dbd-4479-9d39-0f719fb3e9d8

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: