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)

019abfe5-e86e-7c4a-bb2a-2642d193594a
019abfe5-e86e-7dd3-a7b4-453eb883d1ec
019abfe5-e86e-7f13-ba33-9782f3c5aef2
019abfe5-e86f-7032-bae6-69fa85d4eeb9
019abfe5-e86f-7154-aca5-3ec9fd483216
019abfe5-e86f-726f-8e5b-677949a1e857
019abfe5-e86f-738a-89a9-2e5f62daa573
019abfe5-e86f-74a4-aca2-9b03889f1376
019abfe5-e86f-75bf-9e65-928ce41bda7f
019abfe5-e86f-76da-acf6-7dccc1de86e6
019abfe5-e86f-78c9-acf7-73096c09e667
019abfe5-e86f-79e8-be9f-c82be33c0ead
019abfe5-e86f-7bc7-a77b-c9aedea59d50
019abfe5-e86f-7ce6-9ef4-4fc6e2515a93
019abfe5-e86f-7e00-bc56-48bc44766865

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)

1f0caba1-848d-65e8-b2c6-4cf95d479851
1f0caba1-848d-678c-b2c6-4cf95d479851
1f0caba1-848d-6872-b2c6-4cf95d479851
1f0caba1-848d-693a-b2c6-4cf95d479851
1f0caba1-848d-69f8-b2c6-4cf95d479851
1f0caba1-848d-6ab6-b2c6-4cf95d479851
1f0caba1-848d-6b74-b2c6-4cf95d479851
1f0caba1-848d-6c32-b2c6-4cf95d479851
1f0caba1-848d-6cf0-b2c6-4cf95d479851
1f0caba1-848d-6dae-b2c6-4cf95d479851
1f0caba1-848d-6eda-b2c6-4cf95d479851
1f0caba1-848d-6fac-b2c6-4cf95d479851
1f0caba1-848e-6060-b2c6-4cf95d479851
1f0caba1-848e-611e-b2c6-4cf95d479851
1f0caba1-848e-61d2-b2c6-4cf95d479851

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)

76168ff1-f39c-4c43-b8d5-f32872096024
bebe2174-955c-43f7-b10b-0dcfc46f2dab
f2c88043-6b94-4ae2-a097-1e99dbea0675
baf179e6-0fdd-474c-93cd-c6d0a2d302d4
9547174f-c047-477f-91c3-9a6e0ba9fe5e
244e2c74-a918-49e8-9515-87f38067a154
7fb3ca2e-d345-4a4b-b1fe-41e9b218d41a
af64077c-25f0-412d-96f0-4a08b3f91b79
0a27ee78-63b6-481b-864f-e64cd13a3081
d814a83a-35cb-40a9-a737-332260302b81
97678e50-c0a4-46c9-b457-efd25fb8de21
e2f98dbd-2281-45a2-a6e7-1914e2829c5c
8319beb2-e13b-4e1a-a0ce-10d6a9b068bd
aab50582-e416-4cb4-b062-5a7b58c5cf4b
9aac06b9-cbc5-4dfd-a6ba-5a6db1922527

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)

1848e6f0-caba-11f0-b2c6-4cf95d479851
1848e754-caba-11f0-b2c6-4cf95d479851
1848e7b8-caba-11f0-b2c6-4cf95d479851
1848e812-caba-11f0-b2c6-4cf95d479851
1848e880-caba-11f0-b2c6-4cf95d479851
1848e8e4-caba-11f0-b2c6-4cf95d479851
1848e93e-caba-11f0-b2c6-4cf95d479851
1848e9a2-caba-11f0-b2c6-4cf95d479851
1848ea06-caba-11f0-b2c6-4cf95d479851
1848ea60-caba-11f0-b2c6-4cf95d479851
1848eac4-caba-11f0-b2c6-4cf95d479851
1848eb28-caba-11f0-b2c6-4cf95d479851
1848eb8c-caba-11f0-b2c6-4cf95d479851
1848ebe6-caba-11f0-b2c6-4cf95d479851
1848ec40-caba-11f0-b2c6-4cf95d479851

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)

d636dd2e-aa02-8a14-87e9-5ce32bd83b97
1aa6de2e-aa02-8a14-87e9-5ce32bd83b97
87fddf2e-aa02-8a14-87e9-5ce32bd83b97
065be02e-aa02-8a14-87e9-5ce32bd83b97
e64ce12e-aa02-8a14-87e9-5ce32bd83b97
c7b0e22e-aa02-8a14-87e9-5ce32bd83b97
5bc6e32e-aa02-8a14-87e9-5ce32bd83b97
f77ce42e-aa02-8a14-87e9-5ce32bd83b97
6591e52e-aa02-8a14-87e9-5ce32bd83b97
ecb5e62e-aa02-8a14-87e9-5ce32bd83b97
5365e72e-aa02-8a14-87e9-5ce32bd83b97
1737e82e-aa02-8a14-87e9-5ce32bd83b97
0b79e92e-aa02-8a14-87e9-5ce32bd83b97
da7fea2e-aa02-8a14-87e9-5ce32bd83b97
c743eb2e-aa02-8a14-87e9-5ce32bd83b97

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

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: