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)

01a01a7c-c5f1-72d1-afa8-a7a20bcd94d1
01a01a7c-c5f1-746b-9ea4-7292559940dd
01a01a7c-c5f1-75aa-bd89-87d2e7318d04
01a01a7c-c5f1-76c5-b9ce-4b93afb84527
01a01a7c-c5f1-77dc-aa20-4f53d854390a
01a01a7c-c5f1-78f2-91c6-366177d6a535
01a01a7c-c5f1-7a09-9eee-ca71d7867867
01a01a7c-c5f1-7b1f-9087-06b8b71b9826
01a01a7c-c5f1-7c3e-863f-0a7204abcbdf
01a01a7c-c5f1-7d54-9cca-4fae3c351371
01a01a7c-c5f1-7e67-8dcd-2b5858c6a358
01a01a7c-c5f1-7f7d-b55d-0e4300a8073e
01a01a7c-c5f2-709c-a95d-c79c0a8cc988
01a01a7c-c5f2-71cb-9dbb-9718a5996005
01a01a7c-c5f2-72e2-b941-6c6635f59f4a

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)

1f19bdcb-d758-681a-8533-4cf95d479851
1f19bdcb-d758-69e6-8533-4cf95d479851
1f19bdcb-d758-6acc-8533-4cf95d479851
1f19bdcb-d758-6b9e-8533-4cf95d479851
1f19bdcb-d758-6c5c-8533-4cf95d479851
1f19bdcb-d758-6d24-8533-4cf95d479851
1f19bdcb-d758-6e00-8533-4cf95d479851
1f19bdcb-d758-6f04-8533-4cf95d479851
1f19bdcb-d759-6076-8533-4cf95d479851
1f19bdcb-d759-617a-8533-4cf95d479851
1f19bdcb-d759-62d8-8533-4cf95d479851
1f19bdcb-d759-63a0-8533-4cf95d479851
1f19bdcb-d759-645e-8533-4cf95d479851
1f19bdcb-d759-651c-8533-4cf95d479851
1f19bdcb-d759-65da-8533-4cf95d479851

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)

bd7596b6-9bdc-11f1-8533-4cf95d479851
bd75971a-9bdc-11f1-8533-4cf95d479851
bd759774-9bdc-11f1-8533-4cf95d479851
bd7597d8-9bdc-11f1-8533-4cf95d479851
bd75983c-9bdc-11f1-8533-4cf95d479851
bd759896-9bdc-11f1-8533-4cf95d479851
bd7598fa-9bdc-11f1-8533-4cf95d479851
bd759954-9bdc-11f1-8533-4cf95d479851
bd7599ae-9bdc-11f1-8533-4cf95d479851
bd759a12-9bdc-11f1-8533-4cf95d479851
bd759a6c-9bdc-11f1-8533-4cf95d479851
bd759ad0-9bdc-11f1-8533-4cf95d479851
bd759b3e-9bdc-11f1-8533-4cf95d479851
bd759ba2-9bdc-11f1-8533-4cf95d479851
bd759c06-9bdc-11f1-8533-4cf95d479851

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)

02dfe313-7703-870e-87ea-5ce32bd83b97
88dde413-7703-870e-87ea-5ce32bd83b97
20bce513-7703-870e-87ea-5ce32bd83b97
5457e613-7703-870e-87ea-5ce32bd83b97
78ade813-7703-870e-87ea-5ce32bd83b97
72a2e913-7703-870e-87ea-5ce32bd83b97
626cea13-7703-870e-87ea-5ce32bd83b97
2d6deb13-7703-870e-87ea-5ce32bd83b97
0ae1ec13-7703-870e-87ea-5ce32bd83b97
24feed13-7703-870e-87ea-5ce32bd83b97
43c1ee13-7703-870e-87ea-5ce32bd83b97
8bb6ef13-7703-870e-87ea-5ce32bd83b97
2137f013-7703-870e-87ea-5ce32bd83b97
7ff3f113-7703-870e-87ea-5ce32bd83b97
d1abf213-7703-870e-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)

e8edc86f-4234-4fbb-ab09-543bdd1c131b
229c9f2c-d37f-4e73-80ff-ef1f06992862
1544a703-46cd-4bbe-a196-ecbb2de2a5d4
e58f5a0c-c25d-41c7-9b28-e1e30baa3bbd
14ecfd4e-ddac-437a-ae40-092f7162a867
a9ed1016-41f0-4d88-937a-da46a1ada3ed
d1d8dea8-13f1-486c-b944-3a19c39775c4
e3cc5149-11f8-4c74-be15-2b56db13d86c
8e8f9425-7bf0-4df8-8509-9ced2dedc911
efa65e4d-098b-475c-8d4e-811d6d4c9839
e931f6f9-9915-4d22-8c13-2e1a3a021787
963e62e2-4a9e-439e-ba4f-d8ec4b73610a
0f4991f1-f4d1-47d5-be42-3c08f0e86993
db704af9-97fb-4ad7-bc5c-0e7395268a40
df1b689e-4b85-4ce2-90a2-f1f1bb821056

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: