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)

019bf321-74c5-72de-bf97-a435ae952524
019bf321-74c5-74a4-a400-bd5a9ed7d8a6
019bf321-74c5-75e4-bec4-1a1a1427be46
019bf321-74c5-7703-947c-5463a19b765e
019bf321-74c5-781d-852b-3f689e123499
019bf321-74c5-7938-bcdf-71e6ef31738a
019bf321-74c5-7a5b-9bfe-03369a689758
019bf321-74c5-7b71-b77b-05a7b984859c
019bf321-74c5-7c8c-9199-5478b3300919
019bf321-74c5-7da2-b9b8-893da31c5d70
019bf321-74c5-7eb9-a0df-1f33582a8b0f
019bf321-74c5-7fd3-a347-be3deb9d6156
019bf321-74c6-70ee-9857-6f9184316949
019bf321-74c6-7205-a001-2fa784738050
019bf321-74c6-731b-bf26-f87e44b22cd4

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)

1f0f99b5-e62c-6344-b643-4cf95d479851
1f0f99b5-e62c-64f2-b643-4cf95d479851
1f0f99b5-e62c-65d8-b643-4cf95d479851
1f0f99b5-e62c-66a0-b643-4cf95d479851
1f0f99b5-e62c-679a-b643-4cf95d479851
1f0f99b5-e62c-686c-b643-4cf95d479851
1f0f99b5-e62c-6934-b643-4cf95d479851
1f0f99b5-e62c-69fc-b643-4cf95d479851
1f0f99b5-e62c-6aba-b643-4cf95d479851
1f0f99b5-e62c-6b82-b643-4cf95d479851
1f0f99b5-e62c-6cc2-b643-4cf95d479851
1f0f99b5-e62c-6d94-b643-4cf95d479851
1f0f99b5-e62c-6e5c-b643-4cf95d479851
1f0f99b5-e62c-6f1a-b643-4cf95d479851
1f0f99b5-e62c-6fd8-b643-4cf95d479851

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)

ba313e9a-8404-47ce-bba1-e23b496aecb2
c86bc549-8341-4b79-9a3e-73f3f2f7d975
f325e036-b48f-4bf9-bd3d-b92851931cd5
3a096e62-5c0a-4bb0-ac8a-c4ca6117d5d9
6fdad912-2bfc-4aea-b521-4d06692e0145
127e0511-675d-4872-8bc1-7c2c1bf752da
4ded4cfc-ab72-4b3a-9675-d83d176ec939
5f5de957-156c-4922-a0ee-e7e5acd61bef
3e72dba4-d9eb-4b21-ae7b-1728bfedcc18
26d5e0c3-101b-4e93-a914-198c95e971a9
33b18804-3530-4ec7-8c22-6ace5623f7eb
4cc29457-3ce5-4604-a7e3-a2318f1a64f1
22043b3d-977f-4a1f-9600-e0c18266384f
dd7b77d4-6464-4a65-b01e-96e760fcb224
118ec774-6e5d-4968-a06b-1d573f74d296

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)

5e62d4ec-f99b-11f0-b643-4cf95d479851
5e62d550-f99b-11f0-b643-4cf95d479851
5e62d5b4-f99b-11f0-b643-4cf95d479851
5e62d60e-f99b-11f0-b643-4cf95d479851
5e62d672-f99b-11f0-b643-4cf95d479851
5e62d6d6-f99b-11f0-b643-4cf95d479851
5e62d730-f99b-11f0-b643-4cf95d479851
5e62d78a-f99b-11f0-b643-4cf95d479851
5e62d7ee-f99b-11f0-b643-4cf95d479851
5e62d852-f99b-11f0-b643-4cf95d479851
5e62d8c0-f99b-11f0-b643-4cf95d479851
5e62d924-f99b-11f0-b643-4cf95d479851
5e62d988-f99b-11f0-b643-4cf95d479851
5e62d9e2-f99b-11f0-b643-4cf95d479851
5e62da46-f99b-11f0-b643-4cf95d479851

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)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 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) = WRONG!!!
-  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 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)

ccf3b90e-bf00-8901-87ea-5ce32bd83b97
a103bb0e-bf00-8901-87ea-5ce32bd83b97
1575bc0e-bf00-8901-87ea-5ce32bd83b97
6788bd0e-bf00-8901-87ea-5ce32bd83b97
2d2abe0e-bf00-8901-87ea-5ce32bd83b97
f32dbf0e-bf00-8901-87ea-5ce32bd83b97
b9f1c00e-bf00-8901-87ea-5ce32bd83b97
08dfc10e-bf00-8901-87ea-5ce32bd83b97
0969c20e-bf00-8901-87ea-5ce32bd83b97
cebbc30e-bf00-8901-87ea-5ce32bd83b97
7c4fc40e-bf00-8901-87ea-5ce32bd83b97
057ec50e-bf00-8901-87ea-5ce32bd83b97
2d33c60e-bf00-8901-87ea-5ce32bd83b97
5054c70e-bf00-8901-87ea-5ce32bd83b97
92d6c80e-bf00-8901-87ea-5ce32bd83b97

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: