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)

019bbbf8-98f4-74a8-bf76-b7b5b4fbc840
019bbbf8-98f4-7652-a7a3-e0cde7a660ed
019bbbf8-98f4-779a-8cb8-020b8d1e9da5
019bbbf8-98f4-78bd-8baa-408fe73954ec
019bbbf8-98f4-79dc-8f93-80d63fb024b3
019bbbf8-98f4-7afa-9d8d-2d1371a8d9fa
019bbbf8-98f4-7c19-af2f-a7a73638e4cc
019bbbf8-98f4-7d38-bb8c-bb6601a91da3
019bbbf8-98f4-7e5b-9fc4-cf450a02b10f
019bbbf8-98f4-7f79-8e39-ca892cc2eb1d
019bbbf8-98f5-7094-8765-fe36833332a0
019bbbf8-98f5-71af-8117-029c671f802c
019bbbf8-98f5-72d1-b004-3d1e01840d98
019bbbf8-98f5-73f0-a486-7dd46c606da9
019bbbf8-98f5-750b-b716-169d1b6ffc6c

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)

1f0f130b-2583-627c-be2a-4cf95d479851
1f0f130b-2583-6434-be2a-4cf95d479851
1f0f130b-2583-651a-be2a-4cf95d479851
1f0f130b-2583-65e2-be2a-4cf95d479851
1f0f130b-2583-66aa-be2a-4cf95d479851
1f0f130b-2583-6772-be2a-4cf95d479851
1f0f130b-2583-6830-be2a-4cf95d479851
1f0f130b-2583-68f8-be2a-4cf95d479851
1f0f130b-2583-69b6-be2a-4cf95d479851
1f0f130b-2583-6a74-be2a-4cf95d479851
1f0f130b-2583-6c0e-be2a-4cf95d479851
1f0f130b-2583-6d26-be2a-4cf95d479851
1f0f130b-2583-6df8-be2a-4cf95d479851
1f0f130b-2583-6eb6-be2a-4cf95d479851
1f0f130b-2583-6f74-be2a-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)

a2915447-c630-449d-86b8-dff4f67cbc64
794fe3f3-0361-4358-aad8-53edd035d566
17ee83c3-a412-40c6-beb1-939aaa87268a
131f07a4-0972-42a8-a741-a2c5f2b03ba4
c6dfc6ba-01e3-4651-aba5-7b9631db72b4
dd35d5e7-c970-4ed6-a273-d383a41a7b88
b52027c2-2bd5-4870-916e-28c2059898a9
f9f97a3b-a600-4724-92c5-430ac55a3890
e482343c-5064-4e33-9480-fa549e76da80
27fa5318-ba67-4789-9cd9-188547d6efea
8b86cce6-eb48-417b-86ee-50194611ffef
33229131-d0cc-4add-b8d3-d60d4c73a076
bd2b3541-33d8-45a9-8783-6b754cb0d779
44a31a63-3e95-46db-a5fb-6e06c5fb7aa6
b0c8ae29-dc1b-447f-91be-010059cc5f6a

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)

b25844a6-f130-11f0-be2a-4cf95d479851
b2584514-f130-11f0-be2a-4cf95d479851
b25845d2-f130-11f0-be2a-4cf95d479851
b2584640-f130-11f0-be2a-4cf95d479851
b258469a-f130-11f0-be2a-4cf95d479851
b25846fe-f130-11f0-be2a-4cf95d479851
b2584758-f130-11f0-be2a-4cf95d479851
b25847b2-f130-11f0-be2a-4cf95d479851
b2584816-f130-11f0-be2a-4cf95d479851
b2584870-f130-11f0-be2a-4cf95d479851
b25848ca-f130-11f0-be2a-4cf95d479851
b258492e-f130-11f0-be2a-4cf95d479851
b2584988-f130-11f0-be2a-4cf95d479851
b25849ec-f130-11f0-be2a-4cf95d479851
b2584a46-f130-11f0-be2a-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)

d58c221e-5f02-8e00-87ea-5ce32bd83b97
2169231e-5f02-8e00-87ea-5ce32bd83b97
9331241e-5f02-8e00-87ea-5ce32bd83b97
d400251e-5f02-8e00-87ea-5ce32bd83b97
fde0261e-5f02-8e00-87ea-5ce32bd83b97
a4d6271e-5f02-8e00-87ea-5ce32bd83b97
bcc8281e-5f02-8e00-87ea-5ce32bd83b97
45e4291e-5f02-8e00-87ea-5ce32bd83b97
b21f2a1e-5f02-8e00-87ea-5ce32bd83b97
4fdf2b1e-5f02-8e00-87ea-5ce32bd83b97
272b2c1e-5f02-8e00-87ea-5ce32bd83b97
d41c2d1e-5f02-8e00-87ea-5ce32bd83b97
6e342e1e-5f02-8e00-87ea-5ce32bd83b97
fd50301e-5f02-8e00-87ea-5ce32bd83b97
5d52311e-5f02-8e00-87ea-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: