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)

01a164a3-ec27-74ee-9d75-04238bc49810
01a164a3-ec27-76f2-9f1d-dbb86889eaed
01a164a3-ec27-787f-afaa-de9f39552487
01a164a3-ec27-79c7-b66e-a690ca74b638
01a164a3-ec27-7b03-8e87-aebfd6d38a32
01a164a3-ec27-7c3e-ac87-c9d1f20b1b02
01a164a3-ec27-7d75-aa0b-b08a32d6862c
01a164a3-ec27-7ead-b43c-3da179b000c9
01a164a3-ec27-7fe8-aa13-4dbdb39f7623
01a164a3-ec28-711f-bdbb-a31b353b00ce
01a164a3-ec28-7257-9afb-412ab66ce048
01a164a3-ec28-7392-925c-2768c4d7a80e
01a164a3-ec28-74c9-ad1f-783414f22a38
01a164a3-ec28-7600-af88-8750ccec8444
01a164a3-ec28-7738-913e-c37386893a1b

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)

1f1ce3d5-6ba3-609c-86ec-4cf95d479851
1f1ce3d5-6ba3-6312-86ec-4cf95d479851
1f1ce3d5-6ba3-648e-86ec-4cf95d479851
1f1ce3d5-6ba3-65ec-86ec-4cf95d479851
1f1ce3d5-6ba3-6740-86ec-4cf95d479851
1f1ce3d5-6ba3-68a8-86ec-4cf95d479851
1f1ce3d5-6ba3-6a06-86ec-4cf95d479851
1f1ce3d5-6ba3-6b50-86ec-4cf95d479851
1f1ce3d5-6ba3-6c9a-86ec-4cf95d479851
1f1ce3d5-6ba3-6de4-86ec-4cf95d479851
1f1ce3d5-6ba3-6fce-86ec-4cf95d479851
1f1ce3d5-6ba4-6136-86ec-4cf95d479851
1f1ce3d5-6ba4-6280-86ec-4cf95d479851
1f1ce3d5-6ba4-63d4-86ec-4cf95d479851
1f1ce3d5-6ba4-6532-86ec-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)

56ba46b8-ce3d-11f1-86ec-4cf95d479851
56ba4758-ce3d-11f1-86ec-4cf95d479851
56ba47f8-ce3d-11f1-86ec-4cf95d479851
56ba4898-ce3d-11f1-86ec-4cf95d479851
56ba492e-ce3d-11f1-86ec-4cf95d479851
56ba49c4-ce3d-11f1-86ec-4cf95d479851
56ba4a5a-ce3d-11f1-86ec-4cf95d479851
56ba4b86-ce3d-11f1-86ec-4cf95d479851
56ba4c26-ce3d-11f1-86ec-4cf95d479851
56ba4cb2-ce3d-11f1-86ec-4cf95d479851
56ba4d52-ce3d-11f1-86ec-4cf95d479851
56ba4de8-ce3d-11f1-86ec-4cf95d479851
56ba4e92-ce3d-11f1-86ec-4cf95d479851
56ba4f28-ce3d-11f1-86ec-4cf95d479851
56ba4fbe-ce3d-11f1-86ec-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)

6fb4db2e-1404-8712-87ea-5ce32bd83b97
ee52dc2e-1404-8712-87ea-5ce32bd83b97
6d9ddd2e-1404-8712-87ea-5ce32bd83b97
97c6de2e-1404-8712-87ea-5ce32bd83b97
20d2df2e-1404-8712-87ea-5ce32bd83b97
1c84e02e-1404-8712-87ea-5ce32bd83b97
6526e12e-1404-8712-87ea-5ce32bd83b97
76f1e22e-1404-8712-87ea-5ce32bd83b97
f401e32e-1404-8712-87ea-5ce32bd83b97
353ae42e-1404-8712-87ea-5ce32bd83b97
20aee52e-1404-8712-87ea-5ce32bd83b97
0a8be62e-1404-8712-87ea-5ce32bd83b97
c71ae72e-1404-8712-87ea-5ce32bd83b97
9c4ce82e-1404-8712-87ea-5ce32bd83b97
9e7ee92e-1404-8712-87ea-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)

837f4698-5487-4451-acd9-41108aebc27d
d18d9b0b-594c-4ca3-9435-dda1d897d4a8
caaa802c-ca32-42e7-ad2d-bfdea55d18a7
d8e191b5-9ecd-4dcf-8af6-a64c95bf5637
24c2027c-255b-4494-b287-63c2670bb5b9
609176e3-ba41-4db2-887c-8fb0287b4031
804b51d4-bbfc-4eb2-b2f9-2668be57b472
5b0041e6-cd74-4eaf-a93f-e8998a97e8e0
a1e3e0ea-0d08-44e9-92da-265939670e11
bd58b25c-c64f-4f16-9c9f-c0906800cf02
7ab4c424-db8b-436d-b573-1673f5bc0abc
f87fb658-8378-4238-bddb-55513d9e219c
efd3a35b-1ddf-44a7-bfd2-5d2fc1620bec
f22f71e0-3908-488b-8c8c-ba0338348759
5887130c-a3a3-4715-b3fc-d83cc2ba389e

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: