UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate random and/or time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate random (version 4) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) 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)

01934e96-75e8-7000-ae2a-22c300fb02cd
01934e96-75e9-7192-9db2-1ae723692c7a
01934e96-75e9-72d5-9bac-5920b5398ce9
01934e96-75e9-73fc-99b2-aba43c13d140
01934e96-75e9-751b-aebc-47aa3ea74e72
01934e96-75e9-763a-8ad2-d2fd820037a3
01934e96-75e9-7754-989b-cb68d77f13f9
01934e96-75e9-786f-af0d-1fd4a89ee8ac
01934e96-75e9-798e-954a-f1651d337b97
01934e96-75e9-7aa8-88be-3351fe9ff35a
01934e96-75e9-7bc7-8f1c-6d399a25d9c8
01934e96-75e9-7ce6-8832-2f956f5df9b9
01934e96-75e9-7e00-9a84-6902bae00632
01934e96-75e9-7f1f-a328-50a2ba583123
01934e96-75ea-703a-9b45-dc2662eb3a2e

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)

1efa7ffe-8df4-691e-83dc-4cf95d479851
1efa7ffe-8df4-6aae-83dc-4cf95d479851
1efa7ffe-8df4-6b9e-83dc-4cf95d479851
1efa7ffe-8df4-6c7a-83dc-4cf95d479851
1efa7ffe-8df4-6d42-83dc-4cf95d479851
1efa7ffe-8df4-6e1e-83dc-4cf95d479851
1efa7ffe-8df4-6ee6-83dc-4cf95d479851
1efa7ffe-8df4-6fae-83dc-4cf95d479851
1efa7ffe-8df5-60f8-83dc-4cf95d479851
1efa7ffe-8df5-61fc-83dc-4cf95d479851
1efa7ffe-8df5-6346-83dc-4cf95d479851
1efa7ffe-8df5-6418-83dc-4cf95d479851
1efa7ffe-8df5-64e0-83dc-4cf95d479851
1efa7ffe-8df5-65a8-83dc-4cf95d479851
1efa7ffe-8df5-6670-83dc-4cf95d479851

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)

f684ef2a-32ea-4488-865d-3bad73ac36e6
a35a298d-492c-4dc6-afdb-c591a4484a8a
dc2f5c8f-a436-48bc-8135-03dbd952d176
90404b91-715d-4d0a-8546-99017d9d9825
aed64dbf-efaa-4532-bfb6-45f39fffe6c1
aec5cd76-9a06-42b1-b594-e37dcc53aab1
d4a918fe-d9f7-488f-9f0b-02ad4cc42fa4
e4851fb7-1acb-48e5-a823-4cdcf8887ef2
5277f8df-57f8-4110-8c76-c32de150b1db
8fe88c91-5a03-4ba2-b79f-db745928d8e9
56310219-fd2a-4240-8488-ca9049bfce1c
05233c9a-ca13-456f-a414-31237abe0a6b
7e5c4418-0fe5-4b1a-8eb1-e3d5a20f89d0
c99ce98b-00e8-4e05-82eb-f5a00f72c12c
965c0086-22e5-4a7c-8448-f0a56df2a6c6

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)

e8df5b98-a7ff-11ef-83dc-4cf95d479851
e8df5bfc-a7ff-11ef-83dc-4cf95d479851
e8df5c74-a7ff-11ef-83dc-4cf95d479851
e8df5ce2-a7ff-11ef-83dc-4cf95d479851
e8df5d50-a7ff-11ef-83dc-4cf95d479851
e8df5dbe-a7ff-11ef-83dc-4cf95d479851
e8df5e22-a7ff-11ef-83dc-4cf95d479851
e8df5e90-a7ff-11ef-83dc-4cf95d479851
e8df5eea-a7ff-11ef-83dc-4cf95d479851
e8df5f4e-a7ff-11ef-83dc-4cf95d479851
e8df5fb2-a7ff-11ef-83dc-4cf95d479851
e8df6016-a7ff-11ef-83dc-4cf95d479851
e8df607a-a7ff-11ef-83dc-4cf95d479851
e8df60de-a7ff-11ef-83dc-4cf95d479851
e8df6142-a7ff-11ef-83dc-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b96

Version 1: Resolution of 1 milliseconds, random part of 16 bits, local timezone, 48 zero bits "signature", NOT UUIDv8 conform:
- 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)

7576b817-02cf-8146-87e8-5ce32bd83b96
ca10b917-02cf-8146-87e8-5ce32bd83b96
5198ba17-02cf-8146-87e8-5ce32bd83b96
d99fbc17-02cf-8146-87e8-5ce32bd83b96
010ebd17-02cf-8146-87e8-5ce32bd83b96
21a0be17-02cf-8146-87e8-5ce32bd83b96
170bbf17-02cf-8146-87e8-5ce32bd83b96
e1bec017-02cf-8146-87e8-5ce32bd83b96
3e48c117-02cf-8146-87e8-5ce32bd83b96
31d2c217-02cf-8146-87e8-5ce32bd83b96
24bec317-02cf-8146-87e8-5ce32bd83b96
8b62c417-02cf-8146-87e8-5ce32bd83b96
f569c517-02cf-8146-87e8-5ce32bd83b96
a552c617-02cf-8146-87e8-5ce32bd83b96
af9ec717-02cf-8146-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: